The Frontier cancellation policy allows for cancellations of flights within 24 hours of booking without incurring any fees, as long as the booking was made at least 7 days prior to the departure date. For cancellations made beyond 24 hours or within 7 days of departure, fees apply. Non-refundable tickets can be canceled for a credit voucher valid for 90 days, while refundable tickets receive a full refund. Changes to flight details might also result in fees. Passengers are advised to review the specific fare rules and policy details when canceling or making changes to their bookings with Frontier Airlines.