At this time Carnival is running a past guest upgrade for new bookings. Have you already booked your cruise as of yet? This upgrade is limited to certain catagories and new bookings only. An example of the upgrade is: you book a 6A you will be upgraded to a 6C, and so forth.
you need to call her every week before the cruise at 5 weeks out to have her check for you, we have gotten some great upgrades for lower prices amonth out from our cruise date ,it depends on how she fill ups with pax.