Was it for the same aircraft, but for a different version? I don't consider it really a downgrade or upgrade at that point. I've seen DC9s float between 30s/40s/50s (sometimes more then once) between purchase and flight, and the same with other aircraft. If it's a change to a CRJ, or from an A319 to a DC9, or something like that, that's a change.

Also, it's a double downgrade if it's only for that flight. I've had a single downgrade for a route that was changing equipment. If you have to change just for that flight, that's double pain.

Steve B.