Plesk has a utility which makes it possible to restart services. E.g. HTTP, FTP, MySQL etc.

To do this you will need to do the following:

1. Log into your Plesk panel. E.g. https://www.example.com:8443

2. Go to "Tools and Settings"

3. Under "Server Management" select "Services Management"

4. Choose the service you wish to restart

5. Use the options to cycle the selected services