I have allocated a payment to the wrong invoice by mistake and need to reverse this transaction. Can you tell me how to do this please

Thanks for joining us here on the Community, lee55

To do this, please open the invoice and click on '1 payment made' showing in the top-right > select the date to open the invoice payment. 

From here, you can select More > Delete to remove the payment - if you had matched the payment to the invoice from the banking screen, this will automatically move the transaction back into the 'For-Review' tab where you can apply it to the correct invoice. 🙂