(a) Any justice of the Supreme Court or any judge of one of the courts of appeals or of a circuit court of the state who desires to be retired pursuant to this article shall file a written declaration relative to his intention to elect such retirement with the Chief Justice of the Supreme Court, who, upon finding the existence of the conditions prerequisite to such retirement, shall endorse his findings thereon and forward said declaration to the Secretary-Treasurer of the Judicial Retirement Fund.
(b) The retiring justice or judge, upon being retired, shall take the oath of office as a retired justice or judge and thereupon become an extra or additional judge of the state. Thereafter, on the request of the Chief Justice, the presiding judge of one of the courts of appeals or the Governor, any such retired justice or judge may serve on the Supreme Court, on either of the courts of appeals or on any circuit court in the state. Such retired justice or judge, when serving on a court in the absence or disqualification of the regular justice or judge, as the case may be, shall have and exercise all the duties and functions of the regular justice or judge for whom he is substituting. When serving on a court for reasons other than the absence or disqualification of the regular justice or judge, the duties of a retired justice or judge shall be as prescribed by the Chief Justice when serving on the Supreme Court or by the presiding judge when serving on a court of appeals or by the presiding judge, when serving in a circuit court; provided, that nothing contained in this provision shall prevent the Chief Justice from assigning a justice or a judge to special temporary duty in other courts. A recital in the minutes of the court that a regular justice or judge is absent or disqualified and that a retired justice or judge is sitting in his place at the request of the Chief Justice, the presiding judge of one of the courts of appeals or the Governor shall be conclusive evidence of his authority to act.
(c) The Chief Justice or any associate justice of the Supreme Court or any judge of a court of appeals or a circuit court who becomes 70 years of age during the term for which he has been elected and is serving, who is qualified to be retired pursuant to this article and who does not at or before the expiration of his term file his written declaration stating that he intends to retire at the end of the term he is then serving shall be deemed to have waived and forfeited his right to receive any retirement benefits under this article. He shall, however, be entitled to a refund of his contributions to the retirement fund.