https://support.communitybrands.com/hc/en-us/community/posts/30755301357453-1-888-829-1467-How-many-days-before-a-United-flight-can-you-change-the-date.
United 𝘈𝘪𝘳𝘭𝘪𝘯𝘦𝘴 allows you to change or cancel your 𝗙𝗹𝗶𝗴𝗵𝘁 within 24 hours (+1-888-829-1467)of booking without any fees, as long as the booking was made at least one week before the 𝗙𝗹𝗶𝗴𝗵𝘁's departure.