Originally Posted by AnselmAdorne
...What it doesn't say is whether an upgrade with a cert at the aiport comes from J (as it would if you did it online) or I. I assume it comes from I??
Any UG at the airport is from the cabin as-a-whole; some refer to it as AeroLotto. If you have a CityPass and have confirmed to J on a flight within the 24hr window, then you can basically change to any flight on the same calendar day. Confirming in J in the 24hr period actually causes the ET to reissue so that you would not be challenged to present any certificate(s). If you were confirmed in I, or wanted to standby at the airport, you will still have to submit any applicable certificate, if it's done correctly.