Navigate to the Comcast self service site -- https://sts.comcast.com/adfs/portal/updatepassword

Enter domain and username where the domain is "cable" and the username is your BPID.

Enter your old password. If you forgot your old password, stop this process and send an email to [email protected] for help.

Set a new password. New passwords must be at least eight characters long and contain uppercase and lowercase letters.   

Click the "Submit" button.