It was a Z fare but Delta messed up the ticket a few hours before the flight and I ended up in Y. I was told that if any seat becomes available (my seat got sold and there were no other seats available in BE) I will be the one to get it. Two seats in BE appeared as available a couple of hours before the flight but at the gate I learned that they have already upgraded two people. The agents looked confused when I asked about my position in the list and told me there are 4 people (Diamonds) ahead of me anyways asking me to board. Indeed, I am a PM.