Cal. Revenue and Taxation Code § 13830.1

In any case in which this state and one or more other states each claims that it was the domicile of a decedent at his or her death, at any time prior to the commencement of legal action for determination of domicile within this state or within 60 days thereafter, any executor, or the taxing official of any such state, may elect to invoke the provisions of this article. That executor or taxing official shall send a notice of that election by registered mail, receipt requested, to the taxing official of each such state and to each executor, ancillary administrator, and interested person. Within 40 days after the receipt of that notice of election, any executor may reject that election by sending a notice, by registered mail, receipt requested, to all persons originally required to be sent a notice of election. When an election has been rejected by an executor, no further proceedings shall be had under this article. If that election is not rejected within the 40-day period, the dispute as to death taxes shall be determined solely as provided in this article. No other proceedings to determine or assess those death taxes shall thereafter be prosecuted in any court of this state or otherwise.