thanks MikeBOS - that's right, hypothetically, I would like to use my BA Avios to book a reward flight on AA. Sorry if I confused things saying "BA Award", but what I am trying to do is to book award travel on AA using BA Avios, and would like to either know how to either change the FF number on a BA-booked ticket on AA from BA Exec Club to AAdvantage (so that I can benefit from my AA PLT status, or my household members can benefit from their AA credit cards that include free checked bag), or find a way to book the ticket and leave the FF number blank so I can attach the AA number directly from aa.com. I had just read other posts saying that once the BA number gets attached, AA makes it hard for folks to swap out the BA number for the AA number (recently, at least). I'm happy to hear after reading yours, Cathay1101 and jms_uk's posts that I should be able to access via Finnair.com.

Appreciate yours, Cathay1101 and jms_uk's data points, so I should have a mechanism to swap out the FF number using the Finnair website for any BA award ticket on any carrier, whether it is BA, AA, CX, etc.

Now, if I could figure out if there's a downside or not to breaking up my BA Household account (so that I can transfer BA->IB and IB->BA). For the meantime, I'm just leaving the orphaned miles in IB and perhaps one day I'll transfer BA->IB to top it off and use. Sadly, BA/IB awards are not the best option for me given the fuel surcharges.. but eventually over time, I'll be able to redeem awards. Thanks again!