Originally Posted by
windowontheAside
It's a good shout to try aa.com but you don't need an AAdvantage account to select seats. Assuming OP has BA status and wishes to use those benefits, they'd do better to keep their BAEC number on the booking.
Did
Blueboys999 change the FF number on the reservation?
I have to say that even on a reservation with my BAEC number on the booking, my instinctive workflow for finding the reservation on AA.com is to go to AA.com, login with my AA account, go to "my trips" then go "find another trip" and enter the PNR.