You might be able to set your case for an early termination of probation, followed by a motion to dismiss your conviction per PC 1203.4. We just did this with a client who was waiting to get into the service but couldn't with a pending case (more serious than yours): we entered a plea pursuant to a plea bargain, he was placed on one day of probation by the judge, and a 1203.4 motion was immediately granted. That client is now serving his country! Consider hiring an attorney to try to do something like this.
It appears that you are too late. First the judge cannot change the charges only the prosecution. Any leverage that you may have was lost once there was an agreement to the plea. With your conviction you would be better served to join a police academy. Good luck.
The response above is not intended as legal advice since it’s impracticable to provide thorough, accurate advice based upon the query without additional details. It is highly recommended that one should seek advice from a criminal defense attorney licensed in your jurisdiction by setting up a confidential meeting. Moreover, this response does not constitute the creation of an attorney-client relationship since this message is not a confidential communication because it was posted on a public website, thereby publicly disclosing the information, which is another reason to setup a confidential meeting with an attorney.
Unfortunately, if you have already pled guilty to the offense, "buyer's remorse" isn't a generally accepted principle to come back to court and change the charge. For many people, collateral consequences of pleading guilty or no contest include loss of employment, deportation and preclusion to be admitted into the military. I don't mean to sound like it's impossible, but I do think you'll need a lawyer to investigate what happened in your case and see if there are any loopholes that might help you get the result you want. I commend you for wanting to serve the country, by the way.