i am flying stl-dfw-lgw-vrn later this month. the lgw-vrn leg is an aa codeshare operated by ba. the return is fco-lhr-ord-stl. the fco-lhr is a ba flilght.
my project today was to reserve seats on the ba legs. here is what i learned:
on ba.com i was not able to access anything using my aa record locator and last name.
the exp desk could not book seats on either leg but they were able to give me my ba record locator(s)--note that i actually had one ba record locator for the outbound aa codeshare/ba flight and a separate one for the return ba flight (this required two calls to the exp desk as they only gave me one the first time).
through manage my booking on ba.com, i was able to access each flight separately using that flights record locator and reserve seats. on both flights i was able to reserve an exit row. the process was simple although i did have to go through everything twice as there were two separate records. my assumption is that i would only have one record locator on ba if both flights were codeshare or if both were regular ba flights.
when i went to aa.com my seat request for the aa code share was in my record but the seat request for the ba flight was showing unassigned even though i have a print out from ba showing the assignment.