California Code, Education Code - EDC § 90034

An indenture may include a clause prescribing a procedure by which the terms and conditions of the indenture may be subsequently amended or modified with the consent of the board and the vote or written assent of the holders of a specified principal amount or specified proportion of the bonds issued and outstanding.The clause may provide for meetings of bondholders and for the manner in which the consent of the bondholders may be given. The clause shall specifically state the effect of the amendment or modification upon the rights of the holders of all of the bonds and interest coupons appertaining thereto, whether attached thereto or detached therefrom.

With respect to any clause providing for the modification or amendment of an indenture, the board may agree that bonds held by the Treasurer, the United States or any instrumentality thereof, or the State of California or any political subdivision thereof (including every municipal corporation, district, public corporation, board or agency of any kind or class) shall not be counted as outstanding bonds, or be entitled to vote or assent, but shall, nevertheless, be subject to any modification or amendment of this type.