# Update a CreditNote

`PATCH /v1/credit_notes/:id`

Updates a CreditNote amount, reason, notes, or linked Invoice. Requires `credit_notes.update`.

**Required API scopes:** `credit_notes.update`

## Parameters

- `id` (path, `string`) (required)
- `Idempotency-Key` (header, `string`) (required) - Client-generated idempotency key. Required for every POST/PATCH write. Replay of the same key with the same body returns the stored response with an `Idempotency-Replayed: true` header. Same key + different body returns `422 idempotency_key_reused`. A duplicate that arrives while the first request is still in flight returns `409 idempotency_conflict` with `Retry-After: 1`.

## Request body (`application/json`)

- `object`
  - `amount` (`integer`) - The CreditNote amount in minor currency units.
  - `clinician_id` (`string | null`) - format: `uuid`; The optional Clinician associated with the CreditNote. Defaults to the Invoice's Clinician when `invoice_id` is set.
  - `invoice_id` (`string | null`) - format: `uuid`; The Invoice to credit or write off. Required when `patient_id` is omitted.
  - `notes` (`string | null`) - Internal notes recorded with the CreditNote.
  - `patient_id` (`string | null`) - format: `uuid`; The Patient associated with the CreditNote. Defaults to the Invoice's Patient when `invoice_id` is set.
  - `reason` (`string`) - enum: `credited_error`, `credited_goodwill`, `credited_other`, `credited_overbilled`, `credited_service_not_delivered`, `written_off_nonpayer`, `written_off_other`; Why the CreditNote is being created. Use `written_off_nonpayer` or `written_off_other` for a writeoff.

### Example

```json
{
  "amount": 20000,
  "reason": "written_off_other"
}
```

## Response `200`

The requested `CreditNote`.

- `object`
  - `amount` (`integer | null`) - The CreditNote amount in minor currency units.
  - `clinician_id` (`string | null`) - format: `uuid`; The Clinician associated with the CreditNote.
  - `created_at` (`string`) - format: `date-time`; An ISO 8601 timestamp in UTC, with a `Z` suffix. For example, `2026-07-01T09:00:00Z`.
  - `credit_note_number` (`string | null`) - The CreditNote number, unique within the Organization.
  - `currency` (`string | null`) - The ISO 4217 currency code.
  - `id` (`string`) - format: `uuid`; The resource's unique identifier, formatted as an RFC 4122 version 4 UUID.
  - `invoice_id` (`string | null`) - format: `uuid`; The Invoice this CreditNote writes off or credits.
  - `links` (`object`) - URLs to related resources.
    - `invoice` (`string | null`) - format: `uri`; The full URL of a related resource.
    - `patient` (`string | null`) - format: `uri`; The full URL of a related resource.
  - `notes` (`string | null`) - Internal notes recorded with the CreditNote.
  - `object` (`any`) - Discriminator value emitted at `object`.
  - `patient_id` (`string | null`) - format: `uuid`; The Patient associated with the CreditNote.
  - `reason` (`string`) - enum: `credited_error`, `credited_goodwill`, `credited_other`, `credited_overbilled`, `credited_service_not_delivered`, `written_off_nonpayer`, `written_off_other`; Why the CreditNote was created. Use a `written_off_*` reason for a writeoff.
  - `updated_at` (`string`) - format: `date-time`; An ISO 8601 timestamp in UTC, with a `Z` suffix. For example, `2026-07-01T09:00:00Z`.

### Example

```json
{
  "id": "26c20218-4ed3-443e-8e0a-979f2cac1057",
  "object": "credit_note",
  "amount": 25000,
  "clinician_id": "00000000-0000-4000-8000-000000000002",
  "created_at": "2026-01-01T09:00:00Z",
  "credit_note_number": "CN-1001",
  "currency": "GBP",
  "invoice_id": "00000000-0000-4000-8000-00000000002a",
  "links": {
    "invoice": "https://api.carebit.co/v1/invoices/00000000-0000-4000-8000-000000000027",
    "patient": "https://api.carebit.co/v1/patients/00000000-0000-4000-8000-000000000004"
  },
  "notes": "Please confirm the appointment by email.",
  "patient_id": "00000000-0000-4000-8000-000000000004",
  "reason": "credited_error",
  "updated_at": "2026-01-01T09:00:00Z"
}
```

## Response `400`

The `Idempotency-Key` header is missing (`idempotency_key_required`) or exceeds 255 characters (`idempotency_key_too_long`).

- `object`
  - `error` (`object`) - The structured details that describe why the request failed.
    - `code` (`string`) - The machine-readable error code.
    - `errors` (`array | null`) - Additional errors from a failed validation.
      - `items` (`object`)
        - `code` (`string`) - The machine-readable code for this validation error.
        - `message` (`string`) - A message that explains this validation error.
        - `param` (`string | null`) - The name of the parameter that caused this validation error, when known.
    - `message` (`string`) - A message that explains the error and how to resolve it.
    - `param` (`string | null`) - The name of the parameter that caused the error, when known.
    - `type` (`string`) - enum: `authentication_error`, `permission_error`, `invalid_request_error`, `rate_limit_error`, `api_error`; The high-level category of the error.

### Example

```json
{
  "error": {
    "code": "resource_missing",
    "errors": [
      {
        "code": "resource_missing",
        "message": "The requested resource was not found.",
        "param": "patient_id"
      }
    ],
    "message": "The requested resource was not found.",
    "param": "patient_id",
    "type": "authentication_error"
  }
}
```

## Response `401`

The access token is missing, invalid, expired, or revoked.

- `object`
  - `error` (`object`) - The structured details that describe why the request failed.
    - `code` (`string`) - The machine-readable error code.
    - `errors` (`array | null`) - Additional errors from a failed validation.
      - `items` (`object`)
        - `code` (`string`) - The machine-readable code for this validation error.
        - `message` (`string`) - A message that explains this validation error.
        - `param` (`string | null`) - The name of the parameter that caused this validation error, when known.
    - `message` (`string`) - A message that explains the error and how to resolve it.
    - `param` (`string | null`) - The name of the parameter that caused the error, when known.
    - `type` (`string`) - enum: `authentication_error`, `permission_error`, `invalid_request_error`, `rate_limit_error`, `api_error`; The high-level category of the error.

### Example

```json
{
  "error": {
    "code": "resource_missing",
    "errors": [
      {
        "code": "resource_missing",
        "message": "The requested resource was not found.",
        "param": "patient_id"
      }
    ],
    "message": "The requested resource was not found.",
    "param": "patient_id",
    "type": "authentication_error"
  }
}
```

## Response `403`

The access token lacks the required scope, or the project is disabled.

- `object`
  - `error` (`object`) - The structured details that describe why the request failed.
    - `code` (`string`) - The machine-readable error code.
    - `errors` (`array | null`) - Additional errors from a failed validation.
      - `items` (`object`)
        - `code` (`string`) - The machine-readable code for this validation error.
        - `message` (`string`) - A message that explains this validation error.
        - `param` (`string | null`) - The name of the parameter that caused this validation error, when known.
    - `message` (`string`) - A message that explains the error and how to resolve it.
    - `param` (`string | null`) - The name of the parameter that caused the error, when known.
    - `type` (`string`) - enum: `authentication_error`, `permission_error`, `invalid_request_error`, `rate_limit_error`, `api_error`; The high-level category of the error.

### Example

```json
{
  "error": {
    "code": "resource_missing",
    "errors": [
      {
        "code": "resource_missing",
        "message": "The requested resource was not found.",
        "param": "patient_id"
      }
    ],
    "message": "The requested resource was not found.",
    "param": "patient_id",
    "type": "authentication_error"
  }
}
```

## Response `404`

Error response.

- `object`
  - `error` (`object`) - The structured details that describe why the request failed.
    - `code` (`string`) - The machine-readable error code.
    - `errors` (`array | null`) - Additional errors from a failed validation.
      - `items` (`object`)
        - `code` (`string`) - The machine-readable code for this validation error.
        - `message` (`string`) - A message that explains this validation error.
        - `param` (`string | null`) - The name of the parameter that caused this validation error, when known.
    - `message` (`string`) - A message that explains the error and how to resolve it.
    - `param` (`string | null`) - The name of the parameter that caused the error, when known.
    - `type` (`string`) - enum: `authentication_error`, `permission_error`, `invalid_request_error`, `rate_limit_error`, `api_error`; The high-level category of the error.

### Example

```json
{
  "error": {
    "code": "resource_missing",
    "errors": [
      {
        "code": "resource_missing",
        "message": "The requested resource was not found.",
        "param": "patient_id"
      }
    ],
    "message": "The requested resource was not found.",
    "param": "patient_id",
    "type": "authentication_error"
  }
}
```

## Response `409`

A concurrent request holds the idempotency lease (`idempotency_conflict`). Retry after the delay indicated by `Retry-After`.

- `object`
  - `error` (`object`) - The structured details that describe why the request failed.
    - `code` (`string`) - The machine-readable error code.
    - `errors` (`array | null`) - Additional errors from a failed validation.
      - `items` (`object`)
        - `code` (`string`) - The machine-readable code for this validation error.
        - `message` (`string`) - A message that explains this validation error.
        - `param` (`string | null`) - The name of the parameter that caused this validation error, when known.
    - `message` (`string`) - A message that explains the error and how to resolve it.
    - `param` (`string | null`) - The name of the parameter that caused the error, when known.
    - `type` (`string`) - enum: `authentication_error`, `permission_error`, `invalid_request_error`, `rate_limit_error`, `api_error`; The high-level category of the error.

### Example

```json
{
  "error": {
    "code": "resource_missing",
    "errors": [
      {
        "code": "resource_missing",
        "message": "The requested resource was not found.",
        "param": "patient_id"
      }
    ],
    "message": "The requested resource was not found.",
    "param": "patient_id",
    "type": "authentication_error"
  }
}
```

## Response `422`

The `Idempotency-Key` was previously used with a different request body (`idempotency_key_reused`), or the request body failed validation.

- `object`
  - `error` (`object`) - The structured details that describe why the request failed.
    - `code` (`string`) - The machine-readable error code.
    - `errors` (`array | null`) - Additional errors from a failed validation.
      - `items` (`object`)
        - `code` (`string`) - The machine-readable code for this validation error.
        - `message` (`string`) - A message that explains this validation error.
        - `param` (`string | null`) - The name of the parameter that caused this validation error, when known.
    - `message` (`string`) - A message that explains the error and how to resolve it.
    - `param` (`string | null`) - The name of the parameter that caused the error, when known.
    - `type` (`string`) - enum: `authentication_error`, `permission_error`, `invalid_request_error`, `rate_limit_error`, `api_error`; The high-level category of the error.

### Example

```json
{
  "error": {
    "code": "resource_missing",
    "errors": [
      {
        "code": "resource_missing",
        "message": "The requested resource was not found.",
        "param": "patient_id"
      }
    ],
    "message": "The requested resource was not found.",
    "param": "patient_id",
    "type": "authentication_error"
  }
}
```

## Response `429`

Too many requests. Retry after the delay indicated by `Retry-After`.

- `object`
  - `error` (`object`) - The structured details that describe why the request failed.
    - `code` (`string`) - The machine-readable error code.
    - `errors` (`array | null`) - Additional errors from a failed validation.
      - `items` (`object`)
        - `code` (`string`) - The machine-readable code for this validation error.
        - `message` (`string`) - A message that explains this validation error.
        - `param` (`string | null`) - The name of the parameter that caused this validation error, when known.
    - `message` (`string`) - A message that explains the error and how to resolve it.
    - `param` (`string | null`) - The name of the parameter that caused the error, when known.
    - `type` (`string`) - enum: `authentication_error`, `permission_error`, `invalid_request_error`, `rate_limit_error`, `api_error`; The high-level category of the error.

### Example

```json
{
  "error": {
    "code": "resource_missing",
    "errors": [
      {
        "code": "resource_missing",
        "message": "The requested resource was not found.",
        "param": "patient_id"
      }
    ],
    "message": "The requested resource was not found.",
    "param": "patient_id",
    "type": "authentication_error"
  }
}
```

## Code samples

```bash
curl -X PATCH "https://api.carebit.co/v1/credit_notes/26c20218-4ed3-443e-8e0a-979f2cac1057" \
  -H "Authorization: Bearer $CAREBIT_ACCESS_TOKEN" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{
  "amount": 20000,
  "reason": "written_off_other"
}'
```

```javascript
const response = await fetch("https://api.carebit.co/v1/credit_notes/26c20218-4ed3-443e-8e0a-979f2cac1057", {
  method: "PATCH",
  headers: {
    Authorization: `Bearer ${process.env.CAREBIT_ACCESS_TOKEN}`,
    "Content-Type": "application/json",
    "Idempotency-Key": crypto.randomUUID(),
  },
  body: JSON.stringify({
  "amount": 20000,
  "reason": "written_off_other"
}),
});

if (!response.ok) {
  throw new Error(`Carebit API error: ${response.status}`);
}

const data = await response.json();
```

```python
import os
import requests
import uuid

response = requests.patch(
    "https://api.carebit.co/v1/credit_notes/26c20218-4ed3-443e-8e0a-979f2cac1057",
    headers={
        "Authorization": f"Bearer {os.environ['CAREBIT_ACCESS_TOKEN']}",
        "Idempotency-Key": str(uuid.uuid4()),
    },
    json={
        "amount": 20000,
        "reason": "written_off_other"
    }
)
response.raise_for_status()
data = response.json()
```

```ruby
require "httparty"
require "json"
require "securerandom"

response = HTTParty.patch(
  "https://api.carebit.co/v1/credit_notes/26c20218-4ed3-443e-8e0a-979f2cac1057",
  headers: {
    "Authorization" => "Bearer #{ENV.fetch("CAREBIT_ACCESS_TOKEN")}",
    "Idempotency-Key" => SecureRandom.uuid,
    "Content-Type" => "application/json"
  },
  body: {
    "amount" => 20000,
    "reason" => "written_off_other"
  }.to_json
)
raise "Carebit API error: #{response.code}" unless response.success?
data = response.parsed_response
```

```php
<?php

$client = new GuzzleHttp\Client();

$response = $client->patch("https://api.carebit.co/v1/credit_notes/26c20218-4ed3-443e-8e0a-979f2cac1057", [
    "headers" => [
      "Authorization" => "Bearer " . getenv("CAREBIT_ACCESS_TOKEN"),
      "Idempotency-Key" => bin2hex(random_bytes(16)),
    ],
    "json" => [
      "amount" => 20000,
      "reason" => "written_off_other"
    ]
]);
$data = json_decode((string) $response->getBody(), true, flags: JSON_THROW_ON_ERROR);
```