lost keys. how to replace ignition key

This vehicle is equipped with a VATS System. This vehicle can have one of 14 different keys If you have lost all keys for this vehicle,"which should never happen",then you will need to.... 1. Preferred Option: Call a mobile Automotive Locksmith to come to your vehicle to originate a new key.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Go to a GM dealership with the proper identification and see if they have the key code on file...............................................................................................................