Let's say you have booked a cruise at a solo rate. As it turns out a friend or family member can go with you. How is that handled rate/wise? If you haven't made your final payment vs if you have? Will they change the total amount due to the cost per person x 2 that applied when you first booked it as a solo? Of course they will add the additional port charges, ec. for the 2nd person, but what about the basic cabin cost? Anyone have experience with this situation?