# Cancel a transaction

Use this function to cancel a transaction that is actively being processed on the PED. For transactions that have already been processed by the Adyen payments platform, use Refund a transaction from the POS - C.

## Function

Name Description
cancel_transaction Call this function to cancel a transaction. The POS application must never assume the final state and should wait for the final state of the transaction as reported by the PED (from the library).

### Parameters

Name Description
terminal_id The terminal ID of the PED.
tender_reference A reference for the transaction to cancel.

### Code example

The declaration of the call to cancel a transaction is:

ADYEN_RESULT cancel_transaction(char * terminal_id, char *tender_reference)