Quick Answer: To restart your iPhone without the power button, go to Settings > General > Shut Down, then slide to power off. You can also ask Siri to restart your iPhone without the button. So, your ...
Restarting your iPhone is usually the quickest cure for everyday annoyances, from apps freezing up to network hiccups. In fact, you should probably be restarting your iPhone more often than you think.
You can use Siri on an iPhone XR, iPhone XS, or iPhone X in two ways: either with the Side button, or through a "Hey Siri" voice command.