To cancel an Allegiant flight ticket, visit the Allegiant website and log in to your account. Go to “Manage Travel” and select the flight you wish to cancel. Follow the prompts to cancel your booking. Note that cancellation fees may apply, and refund eligibility depends on the fare type. If you booked through a travel agency, contact them directly for assistance. For further help, you can also call Allegiant’s customer service. Be sure to review their cancellation policy to understand any potential charges or refund options.