Originally Posted by gjmv
The problem is that KLM promised that there was availability in Y, so I paid for the class upgrade but after having paid, FB says there's no availability.
The problem is that even when they told you there was availability by the time you made your booking then called FB for an upgrade this could have been gone. Sad but this is the way it works, we have voiced our concern but they (AF/KLM) have left it as it is.
In reality though your problem is most likely the fact that reservations (KLM) will just have looked and said yes, there are seats available in Business. I doubt that they will understand what class needs to be available for an upgrade via FB.
Your options are to look at the Seat Availability for your flight (let someone know here and we can check) then decide wether to keep the reservation in the hope that a "D" seat is made available.
Then again I asked the question about upgrades and Classes to FD a few weeks ago and at first got the standards reply that told me
"Upgrades are only available from KLM's most flexible booking classes".
I pointed out that this was not the reply I wanted and was then called by e helpfull agent and told:
"Class B can be upgraded to D and Class S can be upgraded to Z"
This would indicate that I could by an S class ticket and get this upgraded to Z in Business which I don't think is actually the case.