I hold two passports. My stored API contains the info of the passport I use for TATL flights. However, I'll need to use my second passport for an upcoming trip.
Is there any way of storing API for two passports, or must I overwrite my info each time I encounter this situation?
Thanks in advance.

I sometimes have the same issue. Although I find it easy to change the information on-line on BA.com. You cannot have two passports in the system at once. All you have to remember is to change it to the relevent passport a couple of days before travel. So far for me it has not caused any problems but there was usually a week between trips.