This is what I was trying to say a few posts ago, but was beginning to think it never happened to anyone else. I just received my fourth change to a YYZ-YYC flight yesterday - started as 777-300, then A330 1-1-1, then A330 1-2-1, now back to A330 1-1-1. At least this time we got seats across the aisle instead of opposite sides of the plane. Your point is well-taken, since sometimes the original seats are no longer available by the time the advice arrives. As an infrequent AC patron I was puzzled as to what was happening.