You can uninstall an SSL certificate through the Plesk Control Panel.
- Login to your UWS control panel.
- On the top menu go to Services > My Services
- Click on the magnifying glass on the right side of the hosting package containing the domain name you would like to update.
- Near the bottom of the Manage Product page, you will see a button Login to Plesk Control Panel. Click this button.
- This should automatically login to your Plesk Control Panel. If not, login with the supplied username and created password.
- On the Websites & Domains tab of Plesk, expand the domain details by clicking on it.
- Under Security, click on "SSL/TLS Certificates".
- On the SLL/TLS Certificate page, click on Unassign Certificate