You can manage the sites activated on your plugin license in your Account Dashboard.
Select the third tab, Licenses.
In this menu, you’ll see details about your licenses. Click the Manage Sites link.
On the Manage Sites menu, you can see which sites your license is activated on.
You can manually deactivate sites on your license from this menu by clicking the Deactivate Site link.
This menu can also help you keep track of how many remaining spots you have left on your license to add new sites.