Each person on the booking has their own account and they can access their own individual booking on the trip. There is no shared access to individual user accounts.
If you are considering a name change, then the account would remain in your name and the booking would be transferred from one NUCO account to the other. In the meantime, the person you are giving your place to may want to see which booking options you have - you can either show them the booking page (by printing the webpage) or sending them an updated copy of your booking confirmation email with your options listed.
If you'd like a copy of your updated booking confirmation email, just ask us and we can send this over