How do I get rid of a misdemeanor?

I was working at a retail store and two ladies on different occasions came to me at the register and purchased some items. They had a sale tag on them and when I ran the items they came up regular price so I manually made the changes to the sale price. We are allowed to do this when it doesn't come out as a sale item. If it has a clearance tag then we make it that price. These two ladies came back to return the items without the receipt and the items came back as a whole price. They wanted the money back for the items but since they didn't have the receipt they were going to get the full price for the item. I got charged as retail theft for under price an item.