I reserved a hotel for my 2 younger sisters, ages 14 and 17, at a hilton hotel for an event coming up in 3 months. However, my plans have changed and I am no longer able to go with them, but would still like for them to be able to stay at the reserved room. The 17 year old will have turned 18 1 week before the check in date, but cannot reserve the room by herself for by that time as all the rooms will most likely be booked up. Is there a way for me to reserve the room, then make it so my sister(who will have turned 18 by the check in date) to check in and out for the two of them?