Originally Posted by
SWABrian
If you use "old" nonrefundable funds from one reservation to pay on a new reservation, those funds always remain nonrefundable. (Think about it, if you had $400 in non-ref funds, all you would have to do is make a new reservation using a refundable fare, and xfer the non-ref funds over, then cancel and request a refund.)
Oh, you'd better believe that FTers have thought about it. I can't count the number of times I've been asked about this.