California Substitution of Trustee is a legal process which allows a new trustee to be appointed in place of the existing trustee for a trust. The process is governed by California Probate Code Sections 15200-15204. There are two types of California Substitution of Trustee: voluntary and involuntary. A voluntary substitution of trustee is when the beneficiaries of the trust, the settler, and the existing trustee agree to appoint a new trustee. An involuntary substitution of trustee occurs when a court orders that a new trustee be appointed because the existing trustee is unable or unwilling to fulfill their duties. Both types of substitution require the filing of a petition with the court and the court’s approval to appoint the new trustee.