You can't if you only have 1 "good" key. The key has a transponder in it and if there is only 1 "good" key, the Ford scanner (NGS, WDS, etc) has to be used to introduce a new key. The whole routine takes about an hour, thus the labor cost. If you have 2 "good" keys, the process is very simple and can be done in about 1 minute. (it's in the owners manual). The reason for all of this is to make it difficult for car thieves to get the key code from the dealer, cut a new key, and drive off with your car. If it was easy for you, it would be easier for a car thief. The lesson here is to keep 3 "good" keys on hand.