During the 24-hour Risk-Free Cancellation Period: You can change your Flight at no additional cost beyond any price difference. After the 24-hour Risk-Free Cancellation Period: Only the price difference applies for changes. Within 24 Hours of Flight Departure: Changes are possible starting from $75 when available. Note: The policies for the Basic Economy Ticket are more restrictive... https://www.commudle.com/builds/full-list-of-united-airlines-customer-contact-numbers-in-the-usa-2025