My lock cylinder is stuck in the off position, if i was to buy a new one, what is involved in recoding the lock cylinder to work with my key

i got it, it's been a while since i have been on here, it was easy...just install the pins in the new lock etc, u can buy the pins from gm and they have any combo of 1, 2 , 3 etc...and recoding the lock tot he computer was a cinch if anyone needs help with one just ask