There are two fairly easy ways to reboot a Cisco Callmanager linux appliance (AKA CUCM).
The GUI way:
Log into your callmanager admin page and go to the “Cisco Unified OS Administration” in the upper right corner
click on Settings -> Version
click on reboot
The CLI way:
SSH into your Callmanager (I like to use putty)
enter this command “utils system restart”
you’ll be asked to verify, just type “yes”
I personally like th CLI method, because you can see as various services shut down. Another benefit of using the CLI is that once the server is back up, you can SSH in and use the command “utils service list” which will show all the services. Next to each service will be [STARTING] if the service is still starting up, or [STARTED] if it’s up and running. This way you can tell when everything has started back up.
Keep in mind that rebooting a CUCM box takes around 10 minutes.