> For the complete documentation index, see [llms.txt](https://developer.ultimo.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.ultimo.net/api-key-templates/reservations/cancel-reservation.md).

# Cancel reservation

This workflow allows third parties to cancel an existing reservation for a specific room with specified times.

The following required parameter is used in the request.

| Parameter | Description                                           |
| --------- | ----------------------------------------------------- |
| UltimoId  | The internal Ultimo Id of a reservation for the room. |

## Technical details

Basic URL (POST):

`https://customer.ultimo.com/api/V1/Action/REST_CancelReservation`

Header data:

| ApiKey               | Description                                               |
| -------------------- | --------------------------------------------------------- |
| ApiKey               | Request an API key at (application manager or consultant) |
| ApplicationElementId | Fixed value “5d5a10ee-7b14-4dd4-8683-33822ea56f12”        |

Body (example):

```csharp
{
    "UltimoId": "00000006712"
}
```

### Normal response:

{% hint style="success" %}
Status: 200 OK
{% endhint %}

```csharp
{
    "properties": {}
}
```

### Response when the API-key is invalid:

{% hint style="danger" %}
Status: 401 Unauthorized
{% endhint %}

```csharp
{
    "message": "Missing API key",
    "code": "MissingApiKey"
}
```


---

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