To edit, add or remove an Entity you need to go to the Entity page/ tab. You can access this page in two ways:

Via your Account Settings

1. Clicking on the vault name on the top-right corner and select Account Settings
2. Click on the Entity tab

or via your Documents tab

1. All Documents tab > top-right menu > click on "Entities"
   

2. A new menu will be displayed on the right. Click on "Entity Management"