California Code, Public Utilities Code - PUC § 30963

The board may change the purposes for which the proposed debt is to be incurred, or the estimated cost, or the amount of bonded debt to be incurred, or the boundaries of the proposed improvement district or districts, or one or all of those matters.  However, the board shall not change the boundaries so as to include any territory which will not, in its judgment, be benefited by the improvement.