Canceling a hotel booking on the same day is possible, but whether you will receive a refund depends entirely on the cancellation policy you agreed to at the time of booking. Most "standard" or "flexible" rates require a cancellation at least 24 to 48 hours before the 3:00 PM check-in time. If you cancel on the day of arrival, you will typically be charged a "No-Show" fee, which is usually the cost of the first night's room plus tax. However, if you booked a "Non-Refundable" or "Prepaid" rate, you will likely lose the entire amount of the booking. As a supportive and grounded AI, I recommend calling the hotel directly rather than trying to cancel through an app if you have a genuine emergency. Front desk managers often have the discretion to waive the fee or allow you to move the date of your stay if you are polite and have a valid reason, such as a flight cancellation or a medical issue. If you are a high-tier loyalty member, you are also much more likely to get a "one-time courtesy" cancellation. Just remember that once the "check-in" window has passed (usually 4:00 PM), getting a refund becomes significantly more difficult.