If you have already entered a plea and accepted an agreed upon sentence concerning the charges against you which were read onto the record when you were at court at your arraignment, most likely you will be unable to change what you agreed to.However, to be on the safe side, you should consult with a criminal defense attorney about the situation that you are now in and see if he or she believes that you can now change what you apparently agreed to in court. Potentially the charge against you could be dismissed if you satisfy the terms of your probation. Good luck.