Your relationship to Netflix is direct whether you sign up via Xfinity X1 or Flex. So, when you move, you should be able to retain your Netflix subscription. If however, the billing is through Comcast, you will need to update your method of payment to continue using the service. If you move Xfinity services with you, and you are subscribed to an Xfinity TV package with Netflix, you will need to sign in to Netflix again in order to activate the service on your boxes at your new address.