Originally Posted by friedablass

I can confirm that you can do this. I recently booked a random flight (IAH-DFW) using an FFC that expired end of June. I then changed that flight for December to preserve the ticket for future use. This past week I used the change flight feature to sucessfully book a ticket using the value of that booking for July 30 between two completely different city pairs. I hope to actually fly this one and be done with that FFC.