Update your United Mileage Plus Number
Call 1 800 421-4655 (Mileage Plus); when prompted say “balance and transaction”. Give your United Mileage Plus number (original 11 digit number) and they (machine) will give you your NEW United Mileage Plus # (it will be 8 digits, alpha & numerical). If you plan to ever use your miles, you need to go to United Airlines and register your new #. You will be prompted to either update or create a profile. Also, create a password (you can reuse your original password) and you WILL need a PIN to use your mileage for awards.