As per United Airlines cancellation policy, United Airlines allows its passengers to cancel their United Airlines flights up to 24 hours prior to departure without any cancellation charges. United Airlines cancellation policy if a passenger does not turn up for his/her flight, the ticket will be forfeited and no refund will be issued. passengers may request a refund for their canceled flight by contacting United Airlines customer service. The refund will be processed within a specific period depending on the method of payment. Contact United Airlines for more details