Hello,
Just because the passenger can't do it, it doesn't stop the corporation from doing it. Some year in the early 2000s, I was bribed to move a booking from Voyager to Celebrity Century - increased OBC, upgraded cabin and free flights were offered to change. As it happened, Norovirus came as a free 'bonus'!
I can't remember how long after X sold-off the ship but it was overdue.
Regards,
Cublet