United Airlines’ cancellation policy allows free changes or cancellations within 24 hours of booking. For non-refundable tickets, fees may apply unless covered by travel waivers. Refundable tickets and MileagePlus awards offer more flexibility. Policies vary based on fare type and travel circumstances.

https://www.devex.com/people/flexible-cancellations-what-is-the-cancellation-policy-on-united-2093756