I am happy to assist with your request to change the password. Are you looking to change the network password or the password to log directly into the modem and access the features and settings? Both of these options can be changed by logging into our website or through the business services app. https://business.comcast.com/help-and-support/voice/business-voice-mobility-app-features/
Ah, I see! This forum thread should have the information you need: https://forums.xfinity.com/t5/Internet/ANSWERED-How-to-set-up-Port-Forwarding-on-your-Comcast-modem/... . If you have questions or issues when you log into the gateway, please click on my handle (Comcast_Gina) and send me a private message with your name, the business name, the complete service address (including city, state, ZIP, suite number, etc), and the phone or account number and I'd be happy to further assist.