In Pro Fund Accounting, there is a way to unpay an entire Payables payment journal. Click on the Payables module and then click on the Unpay Invoices menu item. Highlight the specific payment journal that you want to unpay by clicking anywhere on the entry. If you need to see the transactions in that journal, then click on the > button next to the journal number. A list will appear of the transactions that are in that specific payment journal. Click on the Unpay selected payment journal button to complete the unpayment process.
Once the unpayment process is finished, all of the invoices that were paid in that payment journal are now considered unpaid. This means that you can make any changes to the invoices, such as changing the dollar amount or distribution account. When you are ready to pay those invoices again, you would pay them through the Pay Invoices menu item.