I've asked a Comcast employee to help you. You should expect a reply in this thread.
It depends on which box TV lineup you are downgrading to. I can help verify this information and provide more details. In order assist you, please send me a private message verifying your first and last name, street address including city state and zip code, and the full account number or phone number associated with your services.
To send a private message click on my name "ComcastChe", then click private message me.