It's the P.A.T.'s system and you need two keys or a computer to make a key to start the car knowing the VIN omly helps you with the key blank. So the only way would be to steel the key or tow it away. I'll tell what I did find I tried my company van (chevy) key in someone elses van and I can open the door but It wouldn't work in the ignition. This seems to be a common problem with GM's.