i had to have the dealer retreive the factory code from the trucks computer.
you can only change to a personal code if you have the factory code, i didint bother changing mine but the instructions are in the manual in the glove box if it came with one or the dealer can help u out with it. by the way because i went to a different dealer then where i bought it, for the code they charged me $50 to retreive it.
good luck
