California Code, Probate Code - PROB § 17455

(1) The transfer of the trust property to a trustee in this state, or the transfer of the place of administration of the trust to this state, will promote the best interests of the trust and those interested in it, taking into account the interest in the economical and convenient administration of the trust.

(2) The transfer will not violate the trust instrument.

(3) The trustee appointed by the court to administer the trust in this state, and to whom the trust property is to be transferred, is qualified, willing, and able to administer the trust or trust property under the trust instrument.

(4) The proper court in the other jurisdiction has approved the transfer if approval is necessary under the law of the other jurisdiction.