Originally Posted by
HibernateNow
I paid $129 extra to select seat 21A in Premium Economy on 777-300ER. (2nd row)
This morning, 20A bulkhead became open, However, to change to 20A, UA wants another $149.
I went to the last page and it asked for $149 payment. There was no mention about what would happen to the original $129 that I already paid for 21A.
Is there a way to make the change by paying just the $20 difference? I have been on hold with United for the last 50 minutes... guess all live agents are busy right now.
Thanks!

Seems like you selected an ECONOMY PLUS seat, not PE.
PE seats are E+ seats on routes that do not sell PE