If you need a wheelchair during your journey, either onboard your flight or at the airport, and you've already booked your ticket, you can request United Airlines wheelchair assistance by using this website. Then, you can pick up the wheelchair you've requested at the ticket counter or wheelchair assistance centre in the lobby. You can also call their customer service number, 1-844-414-9223, which is available 24 hours a day, 7 days a week, for more information.