Thanks! Signing up for BAEC was the key for me, too. With a mere non-BAEC account I could not change the FF number in the booking.
Originally Posted by
QT31415
Thanks all! Called the partner desk and they could see my FF number on the reservation and it was attached to my OW status. Still couldn't select seats. Finally, went and signed up for an BA Executive account (something I've avoided doing, because so many accounts...) and entered all my info including AS FF number. Voila, worked fine. Was able to enter my husband's FF number into the same booking and achieve seat assignments for him too.