Soft resets are usually conducted in an attempt to fix malfunctioning applications or because they're required for software installation.
Soft reset contrasts with hard reset, which removes all user data, settings and applications and returns a device to the same state it was in when it shipped from the factory.
1. Please unlock your screen if it's not unlocked and press and hold power button.
2. Now wait untill this menu will show up:
3. Once you can see this menu you can release the power button, and tap on Reset or Reboot option.
4. And this is it. You succesfully Soft reseted your phone.