Was booked IAHDENIAD two weeks out in full Y waiting for travel office to ticket. Finally was ticketed but at 72 hours out only IAHDEN had PN available and DENIAD only had 3 F seats left. Yesterday I just happen to pull up my reservation and PN opened up PN=1 and immediately snagged it. What I was wondering though is if I hadn't been proactive I assume that I would have probably been stuck in the back. CPU runs at the windows to clear into R but if PN opens up before the windows do you have to manually watch it and your left on your own to process the upgrade? In theory what could have happened is I could have lost out to someone with higher status clearing at their window or whenever CPU runs?