California Code, Health and Safety Code - HSC § 33453

If after the public hearings the agency recommends substantial changes in the plan which affect the general plan adopted by the planning commission or the legislative body, such changes shall be submitted to the planning commission for its report and recommendation to the legislative body within 30 days after such submission. If the planning commission does not report upon the changes within 30 days after its submission by the agency, the planning commission shall be deemed to have waived its report and recommendations concerning such changes.