Originally Posted by
toyotaboy95
Hmm, it seems that in the case of OW FFPs, seat selection is done by the ticketing carrier not the operating carrier as I have said previously (although it applies for *A FFPs).
Just called CX again for another problem (booking disappearing from MPC website). While I was on the line I thought I'd give it another chance with the CX-operated but AA-ticketed flight.
First answer was the same as yesterday: as it is AA-stock AA need to put the request into the system. When I explained that I called AA before and they didn't want to do it because the flight was full the agent said she would give it a try and she was able to put the request into the system.
Conclusion: just keep trying and you might get lucky...