To actually the your question,
If you look at Advanced > DCE > Commands, you will find Halt Device, which is used by the General Info Plugin.
If you send General Info Plugin a Halt Device, with the PK_Device of the core/hybrid, and set Force to R, then the system will reboot. This is how the buttons in the Advanced Options menu work.
This can done in a variety of ways, from sending it via MessageSend, to triggering it via a Timed Event, etc.