You can program this key yourself with one working key.
INSTRUCTIONS TO ADD A DUPLICATE KEY (REQUIRES AT LEAST ONE WORKING KEY)
1. Verify that both keys have a "+" stamped on them.
2. Insert the original, already programmed key in the ignition and start the engine.
3. Wait for the engine to start, turn the key to off and remove the key.
4. Insert the key to be programmed and turn it to on (just shy of starting the vehicle) within 10 seconds of removing the original key.
5. The security light will turn off once the key has been programmed. It may not be apparent if the security light went on due to how quickly the key is programmed. If your vehicle does not have a security light (2004-2007 Grand Prix, Bonneville, Impala) wait 10 minutes and 45 seconds to make sure the key has been programmed.
6. Repeat steps 1 through 5 if you are programming more than 1 key.