At the time of, or after, a defendant has been placed on probation for a felony‑misdemeanor, or “wobbler” offense, the court may declare that the offense is a misdemeanor for all purposes under Penal Code § 17(b)(3), which provides:

 

(b) When a crime is punishable, in the discretion of the court, by imprisonment in the state prison or by fine or imprisonment in the county jail,[53] it is a misdemeanor for all purposes under the following circumstances:

. . .

(3) When the court grants probation to a defendant without imposition of sentence and at the time of granting probation, or on application of the defendant or probation officer thereafter, the court declares the offense to be a misdemeanor. 

[53] Under Penal Code § 17(a), a felony is an offense which is punishable with death or by imprisonment in the state prison; every other crime is a misdemeanor or an infraction.  However, certain offenses, known as alternative felony-misdemeanors or “wobblers,” may be punished either by state prison or by fine or imprisonment in county jail, at the discretion of the trial judge.  People v. Mendez (1991) 234 Cal.App.3d 1773, 286 Cal.Rptr. 216; see People v. Beebe (1989) 216 Cal.App.3d 927, 930, 265 Cal.Rptr. 242.  Where a judgment other than probation or state prison is imposed, the offense at that point becomes a misdemeanor.  Penal Code § 17(b)(1).

Lower Courts of Ninth Circuit

CAL POST CON " SENTENCE " MOTION TO REDUCE FELONY TO MISDEMEANOR
People v. Willis, 222 Cal.App.4th 141, 165 Cal.Rptr.3d 600 (Dec. 16, 2013) (reversing trial court's extension of probation beyond three years from the beginning of his original probation period, where an earlier court treated defendant's offense as a misdemeanor, so the trial court lacked authority to extend his probation period beyond the three- year maximum probation period for misdemeanors).

Other

CAL POST CON " FELONY " MOTION TO REDUCE FELONY TO MISDEMEANOR
People v. Feyrer, No. S154242 Decision of the court of appeal reversing trial court's refusal to grant defendant's request to declare his offense of assault by means of force likely to produce great bodily injury to be a misdemeanor in its order of early termination of probation, is affirmed as the plea agreement did not render inoperative the statute conferring upon the court discretionary authority to declare a wobbler offense to be a misdemeanor where the court initially granted probation by suspending the imposition of a sentence.

CAL POST CON " VEHICLES " REDUCTION FROM FELONY TO MISDEMEANOR " SENTENCE ENHANCEMENTS INAPPLICABLE
A California hate crimes sentence enhancement, under Penal Code 422.75, does not mean that a conviction carries more than a one-year potential sentence, even after it was reduced to a misdemeanor, because once the court reduces the offense from a felony to a misdemeanor, under Penal Code 17(b), and declares it to be a misdemeanor, then by definition it cannot carry a sentence of more than a year. Penal Code 19. The 422.75 enhancement by its terms only applies to felonies. Once the conviction has been reduced to a misdemeanor, the sentence enhancement no longer applies. Thanks to Chris Gauger.