Originally Posted by
osmantrex
Thanks, appreciate the responses. Wasn't being facetious or anything asking if it was reasonable, just have little experience with both OTA-linked stuff as well as credits for partially-flown itineraries. I think the best course of action is to try to use the credit via Amex Travel to book a valid round trip for close to the full amount (eg DEN-LHR), then try to see what I can do with modifying that new reservation.
That's not going to work, twice.
For one thing, this credit is not going to help you book a round-trip DEN-LHR, because the ticket starts in LHR already. So you're talking about LHR-DEN-LHR-DEN, which is going to price out obscenely high, even if you're trying to do it in economy. It's important to understand what your travel credit is -- it's a partially-used ticket. Any new legs that you add to the flight have to combine with what was originally there, and then the whole thing will reprice as a unit as if you had bought it that way.
And for a second thing, to
IAH-OIL-TRASH's point, the new fare rules will be at least as restrictive as your original fare rules.