How to restart scene when Oculus Rift headset is taken off?

Hello,

I'm working on a VR project in Unity 2018.2.2f1 with Oculus Rift.

Frirst i have created  language selecion menu,  by selecting desired language, app starts selected 360 video.
I need to add a function that reloades back to the languge menu when user  takes off the headset. 
How to do that?

Thanks !
Regards