California Penal Code Section 1203.3

• 1203.3. (a) The court shall have authority at any time during the term of probation to revoke, modify, or change its order of suspension of imposition or execution of sentence. The court may at any time when the ends of justice will be subserved thereby, and when the good conduct and reform of the person so held on probation shall warrant it, terminate the period of probation, and discharge the person so held.
  
• (b) The exercise of the court's authority in subdivision (a) to revoke, modify, change, or terminate probation is subject to the following: (1) Before any sentence or term or condition of probation is modified, a hearing shall be held in open court before the judge. The prosecuting attorney shall be given a two-day written notice and an opportunity to be heard on the matter. (A) If the sentence or term or condition of probation is modified pursuant to this section, the judge shall state the reasons for that modification on the record. (B) As used in this section, modification of sentence shall include reducing a felony to a misdemeanor. (2) No order shall be made without written notice first given by the court or the clerk thereof to the proper probation officer of the intention to revoke, modify, or change its order. (3) In all cases, if the court has not seen fit to revoke the order of probation and impose sentence or pronounce judgment, the defendant shall at the end of the term of probation or any extension thereof, be by the court discharged subject to the provisions of these sections. (4) The court may modify the time and manner of the term of probation for purposes of measuring the timely payment of restitution obligations or the good conduct and reform of the defendant while on probation. The court shall not modify the dollar amount of the restitution obligations due to the good conduct and reform of the defendant, absent compelling and extraordinary reasons, nor shall the court limit the ability of payees to enforce the obligations in the manner of judgments in civil actions. (5) Nothing in this section shall be construed to prohibit the court from modifying the dollar amount of a restitution order pursuant to subdivision (f) of Section 1202.4 at any time during the term of the probation.
  
• (c) If a probationer is ordered to serve time in jail, and the probationer escapes while serving that time, the probation is revoked as a matter of law on the day of the escape.
  
• (d) If probation is revoked pursuant to subdivision (c), upon taking the probationer into custody, the probationer shall be accorded a hearing or hearings consistent with the holding in the case of People v. Vickers (1972) 8 Cal.3d 451. The purpose of that hearing or hearings is not to revoke probation, as the revocation has occurred as a matter of law in accordance with subdivision (c), but rather to afford the defendant an opportunity to require the prosecution to establish that the alleged violation did in fact occur and to justify the revocation.
  
• (e) This section does not apply to cases covered by Section 1203.2.