Can you change your plea on a traffic ticket from guilty to not guilty?

You don't plead guilty "on a traffic ticket" unless you post your fine, request a court date, and then fail to show up at the traffic court hearing.You are then automatically adjudged guilty by reason of your failing to appear to defend yourself.

If you DO go to court you may plead not guilty to the offense, and the judge will grant a hearing in which you and the officer will give testimony, and then the judge will render his verdict. If you have previously pled guilty, or forfeited your fine, in court you will have to file a motion to re-open the case.