Cal. Ins. Code § 11525

A solvent domestic incorporated insurer having a paid-in capital represented by outstanding shares of capital stock and issuing, on a reserve basis, nonassessable policies of life insurance or of both life and disability insurance, may convert itself into an incorporated mutual life insurer, or life and disability insurer, issuing nonassessable policies on a reserve basis. To that end it may provide and carry out a plan for the acquisition of the outstanding shares of its capital stock for the benefit of its policyholders, or any class or classes of its policyholders, by complying with the requirements of this chapter.