Several weeks ago I purchased, on AA.com, a multi-leg ticket from JFK-LHR (on AA), then FCO-LHR (on Alitalia) and finally back LHR-JFK (on AA). The ticket was of fare code N.

Since this time, I have noticed that the total fare would be cheaper using BA from FCO-LHR. A major advantage of using BA over Alitalia would be the extra AA miles earned. Since my current Alitalia flight is not an AA codeshare, there will be no earned AA miles.

Is there anyway to get AA to switch the FCO-LHR flight from Alitalia to BA, and if so would there be much of a cost involved.

Thanks,
FlyerBeek