How to restart phone when power button does not work

When driving I saw a dialog that an application power control stopped. Later I realized that the phone Nokia 8 behaves strangely. I cannot go to launcher, switch application and reboot the phone. Back button works, two other buttons have no effect. Volume app and down work. I can use the power button to lock and unlock the screen. But holding it does not bring reboot options. Is there any other way how to reboot the phone?