If your Delta flight delay happens for more than 6 hours, you can discard your trip as per Delta Airlines' cancelation policy. Hope this summary clarifies the Delta flight cancelation rule. Whether you cancel your flight due to an emergency or the airline cancels your flight due to a technical glitch or harsh weather, do not destroy your boarding pass. Call TicketChanges customer service at +1-888-413-6950 to solve any travel-related issue and get a quick refund.