I don't know whether IHG has any rules on this, but my impression is that it's a matter of the hotel's own policy. Sometimes there's a notice posted near the front desk or on a hotel info/rules handout. Sometimes you can find something on the hotel's website. Big USA city/convention hotels IME often have an early checkout fee of $20 - $100 if you don't change your checkout date when you check in (or on the day you check in). Otherwise, often you're supposed to inform them of the early checkout based on the cancellation policy for your reservation. For instance, if you have a 7 night reservation with a 48 hour cancellation deadline but you want to leave 2 days early, you would need to notify the hotel 48 hours before the new check out time or perhaps midnight of day 3. Hotel managers often waive any penalties if there's an emergency or good reason for leaving early. [Some jurisdictions may have innkeeper rules covering such situations.]