Pub. Util. Code, § 105210

The board may provide for the issuance, sale, or exchange of refunding bonds to redeem or retire any bonds issued by the district upon the terms, at the times, and in the manner which it determines. Refunding bonds may be issued in a principal amount sufficient to pay all or any part of the principal of the outstanding bonds, the interest thereon, and the premiums, if any, due upon call and redemption thereof prior to maturity and all expenses of the refunding. The provisions of this article for issuance and sale of bonds apply to the issuance and sale of the refunding bonds, except that (a) no election need be called or held for the purpose of authorizing the issuance of refunding bonds, and (b) when refunding bonds are to be exchanged for outstanding bonds, the method of exchange shall be determined by the board.