Yes, most hotel bookings are fully refundable if you cancel prior to the hotel's cancellation deadline, which often is within 24-48 hours of check in. If you have a reservation that's non-refundable, you might be able to cancel it and receive a refund within a 24-hour period of your booking. Plug in your dates, click on "Search", then use the filter option "free cancellation" to view the top deals on offer near El Zócalo.