you dont have to worry about last names when you are getting on the ship you might want to be on way before your parents or let them board
first and you wait awhile.
they dont call you by name or room number.
to make calls on the ship room to room you dial there room number.
You should know your room numbers from your booking papers that
are in your package you get printed from your TA or if you printed them
out your self.
hope that helps