RCCL sells reasonable upgrades after embarkation check-in is complete at the "pier coordinator's" desk. NCL will sell upgrades from 60 days in to sailing by calling in to NCL and asking for your ship's reaccomodation person. These are negotiable. The price gets better the closer you are to sailing. I bought an upgrade from a balcony to the penthouse suite for $200 per person a week before sailing. They started out wanting $500 apiece.