# CancelAppointmentRequest

Model ID: `CancelAppointmentRequest`

Request body for POST /appointments/{appointment_id}/cancel.

The body is entirely optional — a request with no body keeps the
pre-existing behaviour (each vendor applies its own default cancel
reason; the FHIR-only path never used a reason at all).

Type: `object`

## Fields

| Field | Type | Required | Format | Allowed values | Default | Nullable | Description |
|---|---|---:|---|---|---|---:|---|
| `reason` | `string|null` | No |  |  |  | Yes | Optional free-text reason for the cancellation, forwarded to the vendor where its API accepts one (e.g. Athena's cancel reason). |

## Example

None declared in canonical OpenAPI.