If you want to cancel your flight you are able to do so free of charge within 24 hours of the date of your reservation. Yes, Delta has a cancellation policy that allows passengers to cancel or modify flights under certain conditions. For example, Delta offers a 24-hour risk-free cancellation period, where you can cancel your ticket within 24 hours of booking for a full refund, as long as the flight was booked at least seven days before departure. For more information.