Originally Posted by
futuramadramallama
Many thanks!
And is instant-upgrade only via Manage My Trip, either on the app or website? Meaning it's not shown, then it's not possible--and it's certainly not
this? I have a mileage ticket and Reddit seems to suggest you're SOL in that case--they can't or won't upgrade those.
If it is a ticket booked on miles (avios or otherwise) then you cannot upgrade this via any route in advance of the flight (maybe on the day at check in but i'm not sure about this at all).