I feel like this answer is going to be "no," but I don't think I've ever actually seen this question asked or an answer written out, so here goes: My wife and I are booked CLT-CDG-CLT in February. Got the 30,000 mile Envoy off-peak seats outbound, but coming home the off-peak Envoy was unavailable, so we just booked the 17,500 off-peak coach seats (I booked this a couple months ago). For whatever reason, tonight I happened to do a search as though I was going to book that same flight, and lo and behold, there are 30,000 mile off-peak Envoy seats available on the return now! So is it possible to just pay an extra 12,500 miles per person to move into the Envoy seats on the return? Again, I'm anticipating that I'm going to hear a resounding "no, not without canceling your current ticket, redepositing your miles and paying the $150 redeposit fee, and then rebooking the award"...but never hurts to ask, right?!