Passengers going from Houston can get assistance in making new reservations or modifying their flights by calling the United Airlines Booking Phone Number Houston Airport. The representatives from the airline help with booking the flights, changing the dates, and paying the difference in the fare. If you are in a situation where you need a last-minute itinerary update, or you must rebook because there is a cancellation, then this is the place to be. Throughout the day, the service is available and there is always someone there to help you at Houston Airport.