Cal. Educ. Code § 15190

Whenever the owner of any coupon bond or of any bond payable to bearer presents the bond to the treasurer or other officer of the county in which the district is located, who by law performs the duties of treasurer, with a request for the conversion of the bond into a registered bond, the treasurer or other officer shall cut off and cancel the coupons of the coupon bond, and shall stamp, print, or write upon the coupon bond or other bond payable to the bearer, either upon its back or upon its face, as may be convenient, a statement to the effect that the bond is registered in the name of the owner and that thereafter the interest and principal of the bond are payable to the registered owner.