I recently redeemed a *A reward, via Air Canada Aeroplan, which includes a trip to Bangkok via Frankfurt, and was able to get a Thai booking reference. I can log on, view my seats, and at one time, I was able to change them. However, now I can only see the seats, but not change them again. I've tried two separate browsers from two separate computers but nothing. I don't think this is a technical issue but wondering if it may be due to some restriction with making changes online via another airline?