In order to delete a user's access from a specific SmartBridge, follow these simple steps:
Select the SmartBridge you would like to share access by tapping it's tile. Then tap the three vertical dots button to move to the SmartBridge settings screen.
Select the "Users - # users(s)" tile. If you have 1 other user (besides yourself) added to the SmartBridge, it will indicate 1 user.
Tap the Trash icon next to the user you would like to revoke access.
After a few seconds this user's access will be deleted and their email will disappear from the Users screen.