How do you unlock a 2007 Chevy Avalanche from theft lock?

To unlock a 2007 Chevy Avalanche from theft lock, insert the key into the ignition and turn it to the "On" position without starting the engine. Leave it in this position for about 10 minutes until the security light turns off. After that, turn the key back to the "Off" position, then back to "On" again for a few seconds. This process should reset the theft lock system and allow the vehicle to start normally.