A/P Invoice - Reversing a Credit Card Transfer that was applied to an American Express Vendor with an incorrect amount?

Hello,
We use the A/P Invoice Data Entry to transfer balances from product vendor invoices to various credit cards that have been used to pay off those invoices.
While the A/P Invoice Data Entry is in the open status we can make changes to the invoice transfer amounts.

However, after we have run the A/P Invoice Register we can no longer make edits to the transfer.

What is the correct procedure to go back and make an adjustment to fix the incorrect amount?

Thanks for any suggestions,

Mike

sage 100 erp 2013 5.00.8.0