https://community.nicic.gov/node/42917
United' 24-hour cancellation policy allows travellers to cancel their booking by phone at us ++1^888^829^1467 OR +1-888-829-1467𝗨𝗦𝗔) within 24 hours of purchase and receive a full refund if done at least seven days before the scheduled departure date. What is United cancellation policy?Yes, you can cancel a flight and get a full refund from United by calling their customer service at 1-888-829-1467. You will receive a full refund if you cancel within 24 hours of booking