Create bill: Duplicate transaction (disregard lock period date for creation)

I would like to have the option of saving a copy only of past bills.  Once we have done our BAS our accountant locks our file for previous period and we have recurring bills every 3 months.  I can't simply duplicate and save a copy of the bill and update it I end up having to unlock the file, save and copy, then go back and relock the file, or enter the whole thing manually again.  The ability to save a copy only without touching the existing bill would be very helpful.

"Save Copy only not just save and copy"