AA allowed the dropping of a segment at any time as long as the new origin and destination is in the same pair of regions (ie the award would cost the same). This is dropping a segment, not changing an award; no availability has to be there for the retained segment. (@JonNYC provided the internal documentation when this policy was instituted a few years ago.) Therefore, if I book, for example, BOS-ORD-NRT, by the rule, I can drop BOS-ORD without changing the price, irrespective of award availability when I drop the segment. Before married segment availability, this wasn’t a loophole: if BOS-ORD-NRT was available, ORD-NRT was available, so the only reason to drop BOS-ORD was legitimately changing my mind. AA doesnt tell me when I book that I only got that ticket because of married segment availability, so I expect to be able to drop BOS-ORD. If they’re now saying I can’t, that’s a significant and negative change for those using this drop segment rule as intended (ie not as a loophole to use hidden city award ticketing).