Originally Posted by
flyingeph12
I would call and speak to a different agent. With First Class, you need original booking class, but with Main Cabin you don't.
Alternatively, have you tried doing a same-day change online? I'm not sure it'll work since you're already upgraded, but it's probably worth checking.
Once I’ve been upgraded I’ve never been able to do SDFC online. Always requires agent assist since they essentially downgrade you back into coach and then do the SDFC. Never heard of requiring original booking class. HUCA.