In contrast to SIGN DE a "transaction" (= receipt in SIGN AT) is an atomic unit. receipts in SIGN AT don't have states. A receipt cannot be canceled.
If a mistake happens during the recording of a receipt, you can fix it with an cancellation receipt ("Stornobeleg" in German).
For example, if the cashier enters an incorrect amount of 500 euros, you should create a new receipt of type CANCELLATION with the total gross amounts of -500. This will correct the incorrectly recorded receipt. After that create a new receipt with the correct gross amounts.
