Cal. Probate Code § 850

(a) The following persons may file a petition requesting that the court make an order under this part: (1) A guardian, conservator, or any claimant, in the following cases: (A) Where the conservatee is bound by a contract in writing to convey real property or to transfer personal property, executed by the conservatee while competent or executed by the conservatee’s predecessor in interest, and the contract is one that can be specifically enforced. (B) Where the minor has succeeded to the interest of a person bound by a contract in writing to convey real property or to transfer personal property, and the contract is one that can be specifically enforced. (C) Where the guardian or conservator or the minor or conservatee is in possession of, or holds title to, real or personal property, and the property or some interest therein is claimed to belong to another. (D) Where the minor or conservatee has a claim to real or personal property title to or possession of which is held by another. (2) The personal representative or any interested person in any of the following cases: (A) Where the decedent while living is bound by a contract in writing to convey real property or to transfer personal property and dies before making the conveyance or transfer and the decedent, if living, could have been compelled to make the conveyance or transfer. (B) Where the decedent while living binds himself or herself or his or her personal representative by a contract in writing to convey real property or to transfer personal property upon or after his or her death and the contract is one which can be specifically enforced. (C) Where the decedent died in possession of, or holding title to, real or personal property, and the property or some interest therein is claimed to belong to another. (D) Where the decedent died having a claim to real or personal property, title to or possession of which is held by another. (3) The trustee or any interested person in any of the following cases: (A) Where the trustee is in possession of, or holds title to, real or personal property, and the property, or some interest, is claimed to belong to another. (B) Where the trustee has a claim to real or personal property, title to or possession of which is held by another. (C) Where the property of the trust is claimed to be subject to a creditor of the settlor of the trust. (b) The petition shall set forth facts upon which the claim is based.