United Airlines executives will do their best to accommodate all your demands. In fact, for some special occasions, you may be able to change your already booked tickets without paying any extra charges. However, for this, you will need proper documents. Passengers simply need to dial United Airlines' official phone number +1-866-901-7017. The customer service team will do their best to assist you. Read this blog to know more about 'United How Much to Change Flight'.