Question about Booking 3 in a cabin then making a change

[Little Elm]

I need to go ahead and book our cruise today with myself, husband, and daughter.  Our friends and their daughter are thinking of going as well.  If that happens after we are booked, Can I then book a cabin for my friends daughter (over 21), and then move my daughter (20) in with her?  I am making sure the deposit in refundable/not discounted. What would happen to our cruise fare?

[Sailin_Pirate]

You could call Carnival 5 times and get 5 different answers.

 

Get a pvp and see what they say.

 

Logically the 3rd fare should be refunded and you would pay for the new room with the friend. It could also be switched over with the right employee.

 

Does Carnival have 2 people rooms? You could get booted from a 3 person room into a 2 person /s