@mkachline To apply a customer payment with invoices in a closed period, you do not need to edit the transaction. It is an internal control feature in NetSuite to disallow changes in periods closed to avoid changes in the financial statement balances. In an accounting perspective, application of receipts against receivables doesn't give rise to an accounting entry. The application process can be performed with the following steps: Navigate to: Transactions > Customers > Accept Customer Payments. Select the customer (Customer field). Under Apply tab: Locate the Invoices under Invoices sublist and the Payment under Credit Sublist. Simply select the respective payment and invoices then click Save. If it's a pure payment application. The Payment amount should be $0.00 so not further payment is posted. Hope this helps