In order to hard reset a Nokia Lumia 822, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Nokia Lumia 822 device will be brought back to the default configuration of a brand new device.
1. Power down the phone.
2. Press & hold the Power and Volume Down buttons. Release them when the phone vibrates.
3. After an exclamation mark appears on-screen, press this button sequence: Volume Up > Volume Down > Power button > Volume Down
4. Voila, well done. The phone should now reset'n'restart, completing the hard reset process.