Some questions regarding cancelling 3rd person

Last April, we booked a B2B on Adventure for summer 2018, in 2 connecting balcony cabins. Same cabins both legs. One cabin has a pullout sofa, the other doesn't. Our daughter got her summer class schedule and syllabus over the weekend. She will not be able to do the first leg.

I'm probably overthinking this, but here goes:

1. She's booked as Guest 3.

2. When we booked, this cabin was only available for 3 (or 4) people, and connects to a 2 person balcony.

3. There are currently no balcony cabins available on this sailing.

So, will cancelling her cause the cabin to be repriced, or will they simply remove Guest 3 from the total? Being as there are no other balconies available, I'm guessing they wouldn't make us move. But would they possibly do so if there were other 2 person balconies available? Should we go ahead and cancel her now, or wait until final payment next month? There's no chance of her situation changing at this point.

You can cancel the 3rd person for a full refund up to 2 weeks before the cruise. I'd wait until a little before then to cancel so there's very little time or options for you to be reassigned to another stateroom.

That puts my mind greatly at ease. I knew I was overthinking this. Thanks for the info!