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618 How can I change the number of people on my reservation? 2010/10/22
If you are adding people to your reservation, and they require additional rooms (in addition to the ones you have already booked), please follow these steps:
1. Make a new reservation at the same hotel for the additional guests.
2. Contact Customer Support after completion with the confirmation numbers for both reservations.
3. Customer Support will combine the your reservations.

If you are adding people to your reservation that will be staying in the same rooms as your original reservation (i.e., no additional rooms are necessary), please do one of the following:
1. Cancel your initial reservation and make a new reservation.
2. Contact Customer Support. Please note that even if you contact Customer Support, it may still be necessary to cancel your initial reservation and make a new one.

If you are subtracting people from your reservation, please do one of the following:
1. Cancel your initial reservation and make a new reservation.
2. Contact Customer Support. Please note that even if you contact Customer Support, it may still be necessary to cancel your initial reservation and make a new one.

Please note that even if you are cancelling a reservation to make a new one, cancellation fees may be incurred. Cancellation policies differ, so please be sure to confirm the cancellation policy of each hotel.

Related:
What cancellation fees apply?