Go to the How To Change A Flight On Frontier Airlines? website and sign into your account to start changing a flight. To locate your reservation, go to the "Manage Booking" or "My Trips" area. To alter your itinerary, choose the exact flight you want to change and adhere to the instructions. As long as the new flight is selected and the price type is selected, fees and pricing variations may apply. Frontier Airlines normally permits flight adjustments up to 24 hours before to departure. Before approving the modification, please read the terms and conditions. Contact Frontier Airlines customer support if you run into any problems or require assistance.