Originally Posted by
ACB777
If Y is oversold on the flight you wish to change to, you will not be able to do so. This applies even if there is room in the J cabin. Note that seats for sale in Y, even on the day of travel, does not equate to the flight not being oversold!
What if EF shows R space in addition to J/C/D/Z?
Can you same day change and immediately confirm an upgrade in one go?