Login to the Modern Hosting Game Panel and select the server you want to manage.
Shut down your server. If you are not sure how to do this, you can read this article here.
On the left sidebar, click on "Settings" (1 in the image below) > "Reinstall Server" (2 in the image below).
4. You will be asked to confirm if you want to reinstall your server. Click "Yes, Reinstall Server" to begin the re-installation process.