Public Utilities Code § 1410
CHAPTER 8. Determination of Just Compensation for Acquisition of Utility Properties
The commission may, at any time subsequent to the filing of the petition, and prior to making and filing its finding as to just compensation, authorize the amendment of the petition by altering or modifying the description of the lands, property, and rights, or by adding to or deducting from the lands, property, and rights, and in each other respect including jurisdictional allegations.