If your son has already entered a plea of no contest or guilty, he will have to do a motion to withdrawal his plea if he wishes to fight the charges now. If he has not yet been sentenced, the Judge can allow him to withdrawal his plea at the judge's discretion. If your son has already been sentenced, he must prove that his plea was the product of coercion or duress, misrepresentation, fraud or mental incapacity. The same judge that took the plea will hear the motion. If the motion is denied, your son can appeal to the 4th District Court of Appeals. It is an uphill battle all the way around.
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I suggest contacting local counsel with experience in appeals. The answer to your question requires an in-depth analysis of the facts and circumstances surrounding the plea.
Once your son waived his rights by entering the plea and signing the rights waiver form, there is very little he can do to appeal. If he was sentenced incorrectly, you could have some rights, or if his lawyer failed to do something that causes irreperable harm, he could have a right to set aside the plea. I will say the rights waiver form, and the plea agreement forms in Palm Beach County are drafted in a way to prevent many of these issues from happening. If you still feel like your son's case deserves some attention, consult a lawyer in the area to see if there truely is something that can be done.
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