Https://mechatronics.ucmerced.edu/sites/g/files/ufvvjh1226/f/webform/1-866-231-4032-united-airlines-check-in-extradetails.pdf https://mechatronics.ucmerced.edu/sites/g/files/ufvvjh1226/f/webform/1-866-231-4032-united-airlines-check-in-extradetails.pdf