Cancel an authorised payment

Cancels the authorisation on a payment that has not yet been [captured](https://docs.adyen.com/api-explorer/#/CheckoutService/latest/post/payments/paymentPspReference/captures), and returns a unique reference for this request. You get the outcome of the request asynchronously, in a [**CANCELLATION** webhook](https://docs.adyen.com/online-payments/cancel#cancellation-webhook). If you want to cancel a payment but don't have the [`pspReference`](https://docs.adyen.com/api-explorer/#/CheckoutSer...