HOW TO CHANGE OR CANCEL A FLIGHT WITH UNITED AIRLINES? FEES & POLICY United Airlines allows passengers to cancel or change flights without a penalty if the action is taken within 24 hours of making the reservation. Here are the critical conditions you need to be aware of: How much does United Airlines charge to change a flight date? After the 24-hour period, United Airlines Change Fees will be $200 to change the date and time of their fligh?s. +1-830-715-0420 (OTA) If your itinerary includes travel within the United States and Canada, there will be no United Airlines change flight fee.