Assumindo que você quer dizer o One World Observatory , em o FAQ diz:
What if I arrive later than my entry time?
Late arrivals will be accommodated based on capacity – you may be required to wait until the first possible open time slot. We strongly encourage you to arrive earlier than your scheduled time to avoid any delays.
Além disso, relacionado à sua pergunta, mas não solicitado:
What is the refund policy? I never used my tickets.
There are no refunds or rain checks for your tickets – tickets must be used on the date/time listed on the ticket. However, if there is poor visibility, the See Forever Commitment ensures you can come on a good day.