Can I Change United Flight date on the same day? The same-day flight change option will be available within 24 hours before your original scheduled flight (+1-888-829-1467 (Toll-free)). The flight you request must be leaving within 24 hours from the time your request is made and can include any fare class, though you may have to pay the difference in fare. Does United Airlines charg... https://oawp.va.gov/forums/general-discussion/f768c050-0338-ef11-a296-001dd8015683