Originally Posted by
orvil
Deadheading Question:
I thought if you were within 24 hours of the flight leaving and there are open seats in first class, you could change your seat to one of the first class seats. I was able to move my reservation to Economy Comfort.
When are you able to move to First?
Oh, BTW, the thunder is rolling in 737/A ATL.

Domestically - never.

Economy Comfort is as good as it gets. You can always put in for an
upgrade to FC (good luck with that) domestically but you can not reserve it.
I am not sure about international but I believe that if a crossing is involved there is some sort of contractual upgrade.
Scoop