Originally Posted by
MSPeconomist
You can cancel a RUC/GUC upgrade request on delta.dumb at any time if the upgrade hasn't yet cleared, although you might need to call DL if you've already checked in. You could also request the GA to skip over you if you cannot be seated together. However, many people will to enable a four year old to sit next to a parent.
You can canel a medallion upgrade request, but there's no way to cancel a RUC/GUC without calling.