Cruise incentive question

[arthur06]

A couple of months ago DW and I added on 125 points and got the 4 night cruise. We are getting ready to book our trip, hoping for Dec 5th Sailing, but are not at all picky! We are wanting to add a person to the cruise and were told it was going to be $100 per person to upgrade to a cat 6. Do I need to pay that when I call or is it due so many days in advance or at check in? Any help would be great, thanks!

 

[ACDSNY]

Our upgrade costs had to be paid when we made the reservation.