At any time after preliminary plat approval and before submission of a final plat, the applicant may request of the Planner or Zoning Administrator that an amendment be made in the approval or conditional approval of the preliminary plat. Under regulations established by the Planning Commission, the Planner or Zoning Administrator may agree to proposed amendments that are deemed to be minor. If the proposed amendment is major, the Planning Commission shall consider the proposed amendment at the next regularly scheduled meeting. The Commission shall approve or disapprove any proposed major amendment and may make any modifications in the terms and conditions of preliminary plat approval reasonably related to the proposed amendment. If the applicant is unwilling to accept the proposed major amendment under the terms and conditions required by the Commission, the applicant may withdraw the proposed amendment. A major amendment shall include, but is not limited to, any amendment that results in or has the effect of decreasing open space in the subdivision by ten percent (10%) or more or increasing density in the subdivision by ten percent (10%) or more. An applicant may not propose more than two amendments-whether major or minor-to any preliminary plat. The Commission shall render a decision on the proposed major amendment within thirty (30) days after the meeting.