Cancel a flight booking

Void a reservation before the ticket is issued.

POST/Air/AirCancel

Access requires the permission air_cancel

Use this on a booking that is held but not ticketed (status 10). Once a ticket is issued, cancel is no longer valid. Refund the ticket instead with refund.

Path parameters

None.

Query parameters

None.

Body parameters

Name	Type	Required	Description
`SessionId`	string	Yes	Your session id.
`UniqueId`	string	Yes	The booking id from book.

Request

curl -X POST https://api.hermeseus.com/api/Air/AirCancel \
  -H "Content-Type: application/json" \
  -d '{
    "SessionId": "8f3c81d2-4a5b-4c6d-9e0f-1a2b3c4d5e6f",
    "UniqueId": "TP-2026-000512"
  }'

const res = await fetch("https://api.hermeseus.com/api/Air/AirCancel", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    SessionId: "8f3c81d2-4a5b-4c6d-9e0f-1a2b3c4d5e6f",
    UniqueId: "TP-2026-000512"
  })
});

const data = await res.json();

import requests

res = requests.post(
    "https://api.hermeseus.com/api/Air/AirCancel",
    json={
        "SessionId": "8f3c81d2-4a5b-4c6d-9e0f-1a2b3c4d5e6f",
        "UniqueId": "TP-2026-000512",
    },
)

data = res.json()

Response

Field	Type	Description
`Success`	boolean	`true` on success.
`UniqueId`	string	The booking id.
`PaymentDeadline`	string	Updated deadline, when the booking stays open.
`Category` / `Status`	integer	Booking category and status after the call.
`CancelationPolicyChange`	boolean	Whether the cancellation policy changed.
`CanExtendPaymentDeadline`	boolean	Whether you can push the deadline out.
`CancellationPolicies`	array of object	The penalty bands that apply.
`CancellationPolicyNoteEn`	string	Human-readable policy note.
`Error`	object	`null` on success.

{
  "Success": true,
  "UniqueId": "TP-2026-000512",
  "PaymentDeadline": "2026-10-10T18:00:00",
  "Category": 10,
  "Status": 10,
  "CancelationPolicyChange": false,
  "CanExtendPaymentDeadline": true,
  "CancellationPolicies": [
    { "FromDate": "2026-09-20T00:00:00", "ToDate": "2026-10-10T00:00:00", "Amount": 0.00, "Currency": "USD" }
  ],
  "CancellationPolicyNoteEn": "Free cancellation until the payment deadline.",
  "CancellationPolicyNote": null,
  "Remarks": null,
  "Error": null
}

Errors

Code	Meaning	Fix
`Err0103003`	Booking not found.	Check the `UniqueId`.
`Err0103004`	The booking cannot be cancelled in its current state.	For a ticketed booking, use refund instead.
`Err0103005`	The booking is already cancelled.	No action needed.