Last time I used the Visa discount, it only worked if the booking consisted entirely of BA prime flights (no other airline flights, no codeshares). BA and AA now allow AA flyers with SWU upgrade instruments to apply them to BA transatlantic flights (no waitlist, so only if space is available). The hitch is that AA can't see the PNR unless there's an AA flight in it (mixed reports if the flight can be an AA code or must be an AA prime). Can I book online with BA prime flights using the discount, then immediately call BA to change the routing to include an AA flight? If I do it right away (within the 24 free cancellation period) would I need to pay the $500 change fee?