Upgrade to E+ on United segment
If I have a United segment on an AC booked itinerary, can I pay to upgrade and confirm an E+ seat as soon as the ticket is purchased?
I have paid for E+ at the airport before at check-in, but want to know if I can do it before hand.
I am booking a ticket and one of my options includes a United segment, which I will do if I can pay and confirm a bulkhead E+ seat. Otherwise I will go for the all AC itinerary.