I have a WT+ booking I've UuA-ed to CW coming up. Is it possible to change the FF# to a different programme so I earn my WT+ miles there? (Thinking of crediting to Alaska Mileage Plan if it makes any difference, which I'm guessing it does not).

Thought of asking on the AS forum, but figured that if there's a wrinkle here it'd be because of how BA treats it due to the UuA, so decided to ask here instead.

Also, best place to change FF#? In the lounge, or at the gate?

Thoughts welcome. Thanks in advance.