Going back and amending the original transaction in past months that have been reconciled can cause problems with your Bank Reconciliations.
To cancel a cheque, enter the same cheque details in the current month but with a negative amount. When you process your Bank Reconciliation, the same cheque number will appear twice, one with a positive amount and the other with a negative amount. Click them both as if they have been presented.
To adjust the amount of a cheque, make the adjustment in the current month. If the cheque amount is more than your records show, the adjustment will be positive, but if it is less the adjustment will be negative. Click both amounts off in the Bank Reconciliation.