I've used HK many times and have had great experiences with them.
The following is the cancellation policy from their website:
Cancellation Policy: In order to afford you the most flexibility in your travel planning there is no cancellation fee if you cancel within 24 hours of booking your reservation, provided that you are still outside of the hotel's Late Cancellation Period, which can range from 3-14 days prior to arrival (some vacation homes have Late Cancellation Period of up to 30 days prior to arrival). After the 24 hours after booking have elapsed, there is only a one-time $10 cancellation fee as long as you cancel outside the hotel's Late Cancellation Period. For cancellations within the Late Cancellation Period (typically less than 72 hours before arrival, with cut-off 3:00 p.m.), the hotel may charge you one room night, plus tax. Exceptions may apply. Please check your individual Hotel's "How to Pay" Page.