Sts. & Hy. Code, § 5896.13

If the work or improvement consists solely of conversion of electric or communication facilities owned or operated by the city and the legislative body has provided that such work or improvement shall be performed by the city or any department, agency, commission or officer of the city, the warrant, assessment and diagram and all bonds issued to represent unpaid assessments shall be delivered to the city and the city shall thereupon have the same rights and liens as the contractor to collect and enforce the payment of the assessments and all bonds issued to represent unpaid assessments. In such event, (a) such warrant, assessment and diagram or (b) any bonds issued or to be issued to represent unpaid assessment, or both (a) and (b), may be sold as the legislative body directs and the purchaser, and any successors, shall thereupon succeed to all of the rights and liens of the city.

If the work and improvement consists, in part, of a conversion and, in part, of other types of work or improvement, the legislative body may provide in the resolution of intention that the costs and expenses of conversion shall constititute part of the incidental expenses to be advanced to the city by the contractor and to be included in the assessment. Any incidental expenses so advanced to the city may be retained by the city for the purpose of paying or reimbursing the city for the cost of such conversion.