Access the Knowledgeable and search for Solution ID:  222924150017495.  It provides three scenarios for deleting or changing an invoice without affecting a prior period.

The scenario you describe is found under Option 3 in that KB article.  Here is the text from Option 3:

Option III: Change the accounting date on the invoice to a current period date, and then make changes to the invoice

1. In Accounts Payable, from the Tasks menu, select Change Invoices.
2. Enter the Vendor and Invoice information.
3. In the Accounting Date column, type a current accounting date. This is the accounting date Accounts Payable uses for your invoice changes.
   • Tip: If you do not have an Accounting Date column, change the date in the Invoice Date or Received date column, depending on your accounting date settings in AP Settings.
   • Note: If you are changing a paid invoice, refer to How do I change distribution information on a paid Accounts Payable invoice?
4. Click Accept invoice without making any other changes.
5. In the Reversal Accounting Date window, select Revised accounting date. This creates debit and credit entries in the current accounting period that net to zero. Click OK.
6. Click Finish.
7. Make the appropriate changes to the invoice as usual in Tasks, Change Invoices. Because you changed the accounting date for the invoice to a current period, the changes you make now do not affect prior accounting periods.

Art MInds
Independent Senior Consultant
Pasadena, California
[email protected]

Thank you very much!