Is there any way to get a undesireable discharge from the us army changed?

in 1972, i was convicted of a felony while in the army. i received a 5 year probation. i was given a choice weather to receive a discharge or start my training over again. like a fool, i chose the discharge. since that time i have cleaned up my life. i have had no further trouble. during the iraq war i worked for kellogg brown and root in balad iraq under a 12 month contract. i furfilled my contract and received great comments from the military. this is the only bad thing that i have and would desperately like to have this mistake changed. does anyone have any suggestions