Originally Posted by
Keyser
this doesn't usually work....even it there is business class redemption available they don't allow you to upgrade....they say 'd' class has to be available in order to do this & 'd' class is generally not available....
Anish is correct. "D" class is also used for pure miles redemptions in business class. If that is available, then the same seat can be used for upgrade redemptions. I have also done this multiple times.