I am traveling KOA-SFO-ORD-DFW on 10SEP. I was originally routed KOA-SFO-DFW but the red eye SFO flight out of KOA was canceled on Wednesdays. UA didn't notify me, I noticed this change when I logged on the website to confirm my seats. I called UA and got a very helpful agent who offered me a full refund or the routing I'm on now.

Anyway, here's my question:

On the KOA-SFO segment the F cabin looks as if there is quote a bit of availability. What do you think my chances of scoring an upgrade are if I mention the problem I had booking this flight? I could have easily taken my refund and went KOA-LAX-DFW on AA but I decided to stay loyal to UA.

Do you think they would grant me the upgrade or rather send the seats out empty?

The availability on all the other segments also look wide open. Should I press my luck and ask for all three or am I getting greedy? After all, I'm just a 2P.

Thanks for the advice!