Originally Posted by
MSPeconomist
This is why I was asking whether the ticket had been reissued. It could make a difference.
No reason why it should for a paid upgrade. Unless I have missed something, I cannot see anything in the Reg to suggest that it does. A complimentary/operational upgrade would be a different matter. Besides, in any event, the OP was placed in economy (rather than the originally booked premium economy). There would still have been a downgrade in any event.