Yes, most room reservations are refundable provided that you cancel prior to the accommodation's cancellation deadline, which in most cases is within 24 or 48 hours of your scheduled arrival. If your reservation is non-refundable, it might still be possible to cancel it and be given a refund within a 24-hour period of your booking. Plug in your dates, click on "Search", then you can filter by "fully refundable" to view the best options available near Great Wall-Yanmenguan Section.