Join Date: Aug 2011
Location: Barcelona, London, on a plane
Programs: IB+ Gold, TK E+, Hyatt Globalist, Marriott LTP, IHG Diamond
Posts: 14,182
Get in touch with the hotel. They might let you adjust the dates for no charge.
I believe it's a general rule of thumb that you have to show up before the hotel's regular check-out time the next morning. But of course you can call the hotel or have HGP put a note on your reservation as well and there shouldn't be any problem.