For a flight on Sunday (AA ticketed on BA flight number), I was able to change to the bassinet seats on RJ.com at T-36. My BA record still shows me at my old seat, while AA and RJ show me in the new seat. ExpertFlyer shows my old seat blocked and new seat taken.

I'm unable to do online checkin for the first leg on AA (likely due to visa checks) so won't get a boarding pass for a while.

Do you think it's ok if the BA record still shows my old seat? Does it take a while to update? I don't want to lose both my new and old seat (most of the cabin is full).

Edit: After about an hour, the BA record changed as well, so I'm happy now.

Thanks aidy for the RJ trick.