Wound up with CX SIN-BKK-CMB. On about the 5th call for this reschedule, one agent did finally bring up the "no change carrier, no change cities" rule so I had to point out I was forced to break that rule by their schedule change. But apparently they weigh the airline change over connection city change. I'm finding AA rather difficult to deal with on the changes. Their agents have generally been the ones suggesting the alternate itins, and the next-to-last one (SIN-KUL-CMB on Malaysian) was booked/ticketed by a supervisor before something in their system (a couple days later) threw it out as invalid and made me call back.