ALBUQUERQUE, N.M. (WHAT THE TECH?) — Imagine being out and finding someone who needs medical help. You reach for their phone – but it’s locked. What do you do?

There’s a little-known feature on most smartphones that makes it possible to not only dial 911 but also to call their emergency contact.

On iPhones, you can find the “Emergency” option at the bottom of the screen. Tap it to open a phone keypad. You won’t be able to call anyone else but you can dial 911. Swipe up again and tap “Emergency” You’ll see “medical ID” at the bottom of the screen. Tapping it should show the person’s name, medications they take, and their emergency contacts.

If they’re wearing an Apple watch, it’s probably unlocked. Even if it isn’t, press and hold the bottom button. Swipe to make an SOS call, which dials 911 and sends a message to their emergency contacts, saying you’ve called for help and shows your precise location.

This work if they’ve set up emergency contacts. If you haven’t done this, you should. Open the “Health” app on an iPhone and tap your picture at the top right. Fill in as much as you think is necessary, especially any medication information that would be important in an emergency. Add your contacts and their phone numbers.

Make sure “show when locked” and “share during emergency call” are turned on.

On Android devices, swipe up on the screen. Then, tap “Emergency call” to see their name, call 911 and view their medical information and emergency contacts. Android phone owners should enter that information.

Be aware, this could be different depending on which Android device you have.

If you have young kids, teach them how to do it. Take an old phone, it doesn’t matter if it’s connected to a phone plan or not. Then, plug it into a charger, connect it to wifi and teach them how to use it.

It could be the only way they can call for help if they can’t unlock Mom or Dad’s phone.

You can also use this if you find the owner of a lost phone. Just be careful not to tap the button that calls 911 automatically.