https://community.expensify.com/discussion/63488/know-the-process/p...
United Airlines offers a few different cancellation options depending on
when you booked your flight and the fare type you purchased. Here's a
breakdown of the key points:

24-hour Free Cancellation: You can cancel your flight for a full refund within 24 hours of
booking, as long as your flight is at least seven days away. This
applies to most fares except Basic Economy.