A related question: can you use the value of a refundable fare to pay for a non-refundable ticket, paying the difference if the nonrefundable fare happens to be more expensive than the refundable one is?
In particular, I'm looking to use the value of a refundable domestic ticket to help pay for a nonrefundable international United codeshare flight.
I know I could just refund the refundable fare, but I'd rather go about it this way.