Originally Posted by
dmodemd
There are wacky things going on with the reservation system when on AS ticket stock and upgrading to MCS. It seems to create another copy of the segment in VX's system (with an MCS booking code) and then should delete the AS segment (which is duplicated in VXs system which is why it needs to get deleted). However, this doesn't always happen properly and you may get duplicate segments when you check on VX website. Then you can't check in.
This, and what was said above, which is that VX does not offer last-seat availability for advance MCS upgrades. They hold back the last few seats and will assign them at the gate.
I'm not as forgiving as some here with the "it'll all be fixed in a few months, so who cares if it's a hot mess now" line... But the admitted good news is that in a few months we will be able to upgrade into VX F...