Age of majority north carolina v alabama

I filed and was Granted a Divorce in Alabama. My Obligation is to pay Child support until age of Majority which in Alabama is 19. Up until 6 months ago, my Son lived with his Mother in North Carolina. He has since changed school Districts and began living with me. He turned 18 3 months ago and just graduated High School. I want to request that in view of the facts, that I no longer have to pay child support as he lives with me. The problem is how can I request to have my child support changed now as he is over the age of Majority 18, in North Carolina. How can a judge order a Child support order changed in North Carolina for an 18 year old? I am not looking for anything from the Mother but for me to stop having to pay her.

Thanks for your help!

File a motion to modify (terminate suport) the current order in AL.