Data point on changes to married segment JAL award tickets. I had F from JFK-HND-KOJ-ITM when I booked the award because JFK to HND wasn't showing availability in the AA app. It's been about a week since I booked that and I called into AA to ask about dropping the HND-KOJ-ITM segments because I didn't want to continue to Osaka. It took me calling a couple times (on the Platinum Pro line) but eventually got a rep who said she could change it. I stressed on the call that I wanted to keep the same PNR and not mess with the JFK-HND segment. She got it reissued, the later segments immediately disappeared from the app, and the MMB page showed as "On Request" on the AA website for about an hour before I got the confirmation email that it ticketed. The JAL MMB page showed ticketed the whole time, and the later segments also immediately disappeared after she changed the booking. So, if you do have to book a married segment, AA reps apparently CAN drop those segments, but you may need to shop around the reps a bit until you find one who knows how to do it.