Ideally you should request it with the provider but in case you have decided to change the password then, follow the below steps. You can also check out the Comcast email login help blog Here in case any other issue persists:
- Go into your web browser and type the IP address 192.168.1.1 In almost all the cases the default user id will be "admin" while the default password shall be "password", but you may have a blank password as well. For more information on what are the probable credentials of your router, Head Here
- Go to Gateway -> Connection -> WiFi and press the EDIT button next to your wireless network.
- Change the Network Name (SSID) and the Network Password to whatever you desire and then press the SAVE SETTINGS button.
- It is always recommended to change the actual router password as well so it's not the default one. Go to Troubleshooting -> Change Password, provide the Current Password, the New Password, and Re-enter New Password and press the SAVE button.