Assuming this issue is in Miami, you can usually contact the judge's chambers by phone and have the matter calendared without a written motion. Alternatively you can ask your probation officer to calendar it, as it is in his/her interest to have one less probationer to supervise.
In either case, make sure that early termination was not addressed in the negative during your initial plea. If it was not addressed, then you at least have a fighting chance. Depending on how much time you have left, it is obviously up to the Court's discretion. If this is a misdemeanor case, I suggest showing up early and trying to speak to one of the prosecutors before the judge takes the bench. Good luck.
I agree that you can call the Judge's Judicial Assistant to calendar the hearing or ask your Probation Officer to set hearing up for you. Typically you must complete one-half of your probation period and have no violations to be terminated early.