Originally Posted by
MSPeconomist
Be careful too not to accept the change that DL proposes.
OTOH, if you wait too long, you risk having fewer choices as flights fill up.
So long as the flight has at least the same number of seats you need, how full the flight is does not matter (unless its sold out). The system will OB the class of service on a schedule change rebooking.
On the PNR viewer next to Previous Action Code you’ll see OB. The system will just overbook the class of service to rebook a schedule change even if that flight is almost filled up.