Welcome to the Big Night Chicago 2023 New Year's Eve Room Block Website. Last Day to Book is 04 Dec 2023. If you are experiencing any issues booking a room, please call Marriott’s Central Reservation System at 1-888-236-2427.72 Hour Cancellation Policy - Individual cancellation on guestrooms is to be made by 4:00pm CST, 72 hours prior to check-in date. If guest cancels after 4:00pm CST, 72 hours prior to check-in date, a cancellation fee of one night's room and tax will be charged. An early departure fee of one night’s room and tax will apply if attendee checks out prior to the confirmed checkout date.