Originally Posted by
KARFA
If the OP has booked a reward flight using a 2-4-1 then a UuA isn't possible. You can only UuA revenue bookings, not reward ones.
I didn't say UUA, but upgrade was probably the wrong choice of words - I was thinking about the goal, not the precise actions to get there. It might be easier to see it as a cancel and rebook (and I know it probably isn't that either).