My wife and I were both upgraded on a flight from Bur to Sea. We didn't check in 24 hours early and late in the evening we wanted to check in for the 11 am flight the next day. Not only were we no longer in first, but we were stuck in middle row seats in economy. We never received an e-mail or phone call due to a late change of planes. After calling the airline and spending considerable time on the phone, we changed to the 7am flight so my wife could still sit in first and I was able to get an exit row aisle seat. We were told that due to a change in service from a 737-800 to a 737-400 there were four less seats and the last people to check in lost their seats. Status did not matter, only check in time since the others already had their boarding passes. This was a first for me. I think it is absurd to let a lower level member keep the upgrade over a top level elite, but that is the way it works in a situation like the one we experienced.