Maybe somebody can help me, as I've been on hold for over 90 minutes on the Silver line. I have an Avios booking for this Sunday (with return later in the month), and I'd like to change the outbound EDI-LHR at 18:05 to an earlier flight. Problem is, there is no redemption availability in Y, though J is available. Is it possible to change and upgrade the Avios booking so I can leave earlier? I'd rather not have to spend so long on the phone only to find out it is not possible.

Thank you!