You can remove a user's access to a client's Hubdoc account in two places: from the 'Manage Users' page on the Partner Portal and from the 'Profile' page inside a client's Hubdoc account.
From the Manage Users page in My Hubdoc
1. Login into Huboc
2. On the Partner Portal, click on the 'Manage Users' button
3. Select the name of the user whose access you wish to revoke
4. Hit the 'Revoke Access' button next name of each client
From the Profile page in Client Account
1. Login into Hubdoc
2. Select a client's name to view their Hubdoc account
3. Click on the 'Accounts' button (top right)
3. Navigate to the 'Profile' page
4. At the bottom of the page, there is a list of 'Current Collaborators' who have access to that Hubdoc account. Click the 'Remove' link next to the user's email address. This user will no longer have access to this client's Hubdoc account.