Need to link, unlink, or switch between your accounts? You can use your Xfinity ID to manage multiple accounts through Xfinity My Account.
Linking enables you to use one Xfinity ID to manage multiple Xfinity accounts/addresses.
If the personal email address or mobile number you provide when creating your Xfinity ID or accepting an invitation to join an account is already on an existing profile, you’ll be prompted with the option to link your accounts, or continue with creating a new profile.
Note: If you do not wish to link your accounts, choose Create a new profile instead to create a separate Xfinity ID for your new account.
In addition, you can link additional accounts that don’t yet have an Xfinity ID to your Xfinity ID in My Account. On the Settings page, go to the Linked Accounts section of Account Details and select the Link Account option. You’ll be asked to provide information about the account you wish to link.
If you wish to link your Xfinity ID to an account that already has an Xfinity ID, request that the primary user on that account invite you to join the account using the email address or mobile number associated with your Xfinity ID. Upon accepting the invite, you’ll be asked to link your existing Xfinity ID to the account.
You can view the accounts your Xfinity ID is linked to by navigating to the Linked Accounts section of Account Details on the Settings page. In order to unlink from an account, you can select the Unlink action next to the desired account. After unlinking, you will no longer have access to Xfinity Services or My Account for that account. To regain access, the primary user for the account will need to add you as a user.
In addition, a primary user can unlink any secondary users from their account by selecting the option to Remove them from the Users view in My Account. See How to Remove An Xfinity ID for more information.
If you have multiple Xfinity accounts that are linked to your Xfinity ID, there are a couple ways to switch between them.
Your primary account is displayed by default. To change the account selected in these apps, one option is to change your primary account. This can be done online in Xfinity My Account by selecting Manage Accounts in the navigation bar located on the top right. You can also change your primary account by selecting Linked Accounts in the Account Details section under Settings. Then, you can view all your accounts and choose a primary account you wish to set as a default across your Xfinity apps (Stream, xFi, Xfinity Home, etc.) by selecting the Make This Primary option.
For xFi and the Xfinity Stream portal, you’ll also be prompted to select your account when signing in. Select the account you’d like to access and click Continue to view that account. If you’d like to switch accounts later, you can sign out and then sign back in to pick another account.
Additional Informaiton:
https://www.xfinity.com/support/articles/switching-between-multiple-accounts