Cal. Sts. & High. Code § 9050

Whenever any principal or interest of any issue of bonds issued under the “Improvement Bond Act of 1915” is past due and unpaid because of delinquency in the payment of assessments, the legislative body of the city in which the property assessed lies may determine by resolution that the public interest or necessity requires the refunding of such issue of bonds, and declare its intention to refund the bonds.