United Airlines Change Flight, United Cancellation Policy: United Airlines is no exception to the 24-hour flexible booking policy. You may cancel or change any flight within 24 hours without incurring additional costs.
Delta Name Change,Delta Change Fees: you have up to 24 hours after booking to cancel your ticket for any reason and receive a full refund with no change or cancellation fees.
https://aviationrepublic.com/blog/united-airlines-change-flight-date/
https://aviationrepublic.com/blog/how-to-cancel-united-airlines-flight-ticket/
https://aviationrepublic.com/blog/delta-airlines-name-correction-policy/
https://aviationrepublic.com/blog/delta-airlines-change-cancellation-and-other-fees-all-you-need-to-know/