“Have a reservation (not pre-paid/third party) that you need to cancel but you’re past the cancellation date/time? Here’s a workaround I have offered to some of my nicer guests:

Call the hotel. Be polite to the person on the phone. Give them your reservation information and tell them that your plans changed and you need to push back your arrival date. If the rate you booked allows it, most front desk agents will do this for you. Change your arrival date to something a week or two out. Then, call the hotel back in a day or two and cancel the reservation.”