A little bit more information is needed for this. Why is it running in reverse? Did you just buy this oven? What voltage do you have?
Reversing the belt is a lot more than just changing the direction. They have assess to the controller locked due to this. To reverse the belt one has to remove the conveyor and turn the belt around. They are only made to go one way without damage and excessive stretching
Recommend you find a Star/Holman service company tech.