DELETE the specified order...

/api/v3/orders/:id

Example result...

{
     "order": {
             "created_at": "2021-09-12T12:34:55Z",
             "custom_order_id": "O123",
             "email": "joe@example.com",
             "first_name": "John",
             "id": 123,
             "last_name": "Doe",
             "updated_at": "2021-09-13T10:11:12Z"
     }
}