Key Off Reversal in Accounts Receivable
You cannot reverse a Key Off, However, you can create another key off reversing the transaction.
Go to the key off routine and start a new Key Off.
Enter the appropriate data at the top of the screen and all open invoices will display
Go to the bottom of the screen and hit the drop down next to the Fully Paid Division-Invoice No field.
Find the invoice that was paid off in error.
Once Found, highlight it then hit the Apply button. This will move the invoice to the right panel of the screen.
The balance will be 0 and the applied amount will be zero.
Key in a negative value that is the same as what was keyed off in the Applied Amount field.
It will return the balance of the invoice to what it was before the key off.
Go to the GL distribution tab (assuming you keyed it off to a GL account) and key in the same amount.
This should negate the first key off and reinstate the invoice.