California Code, Probate Code - PROB § 6605

(a) If proceedings for the administration of the estate of the decedent are pending, a petition under this chapter shall be filed in those proceedings without the payment of an additional fee.

(b) If proceedings for the administration of the estate of the decedent have not yet been commenced, a petition under this chapter may be filed concurrently with a petition for the probate of the decedent's will or for administration of the estate of the decedent, or, if no petition for probate or for administration is being filed, a petition under this chapter may be filed independently.

(c) A petition may be filed under this chapter at any time prior to the entry of the order for final distribution of the estate.