Originally Posted by MSPeconomist

IMO it's unreasonable to expect to keep free elite upgrades when one makes a voluntary change to a ticket. If C+ is full on the new flight, DL certainly should not kick some other customer out of a C+ seat (whether paid or free elite upgrade) in order to accommodate the OP. Just like when a ticket is purchased close to departure, when flights must be changed voluntarily at the last minute, the passenger should not expect necessarily to be able to select a good seat.

It could be somewhat different in the case of IROPs rebookings, if the original flight is cancelled/rescheduled, etc. but the OP needs to change flights because "something has come up."

I suspect that the second post in this thread concerns a rebooking due to IROPs since at least one of the flights was apparently very close to boarding when the change was made since the customer was checked in and the agent had to contact the gate, although I'm confused in that price shouldn't matter when one is being rebooked due to IROPs unless one wants to purchase a higher cabin class.