To change a Frontier Airlines flight, first log in to your Frontier account online or call their customer service line. Frontier Flight Change fees and fare differences may apply depending on the type of ticket purchased. Provide your confirmation code and request your desired changes to flight date, time or destination. Frontier will check availability and assist with modifying your reservation. For more information call a helpdesk at 1 (855) 981-4544 or 1 (844) 902-4930 (OTA-Skip Waiting). Or go the Airlinespetpolicy site.