Can I change a round trip ticket after flew the outbound?
I would like to have a little bit help on the following ticket.
I was booked in MSP-NRT-PEK outbound, PVG-NRT-MSP inbound in L fare. I flew MSP-NRT-PEK last week, and would like to paid the fare difference to be rebooked in M and use miles to upgrade into BE. Is it possible to do such a change? If yes, how would delta calculate the fare difference? Thanks!