In short: Log in to WHM at https://your-server-IP:2087, open System Reboot, and choose Graceful Server Reboot (recommended: stops processes and saves data first). Use Forceful Server Reboot only if the graceful reboot doesn't work, as it can cause errors or data loss.
Log in to WHM at https://your-server-IP:2087 (replace your-server-IP with your server's IP address or hostname) with your username and password.
On the home page, choose System Reboot.
You will see two options: Forceful Server Reboot and Graceful Server Reboot.
Forceful vs graceful reboot
Graceful Server Reboot (recommended): closes all user processes and saves all data before rebooting. Click Proceed.
Forceful Server Reboot: shuts the machine down abruptly and can cause errors and data loss. Use it only if a graceful reboot doesn't work. Click Proceed.
A screen then shows that the reboot is in progress. The server is usually back within a few minutes.
For a Hyyat Host cloud server, you can also reboot from the client area; see the cloud server FAQ.
Related service: server management from Hyyat Host, with support that replies within 24 hours.