Preliminary plat approval. Approval of the preliminary plat shall constitute conditional approval of the subdivision only with regard to its character and density but shall not be construed as approval of the final subdivision plat nor authorization for construction of buildings, the sale or transfer of lots, or the phasing of the subdivision. Furthermore, the approval is not valid until all conditions, if any, are satisfied. Upon approval of the preliminary plat, the applicant shall have two years to obtain approval of a final plat for the subdivision or a phase thereof, which shall conform to all applicable regulations in effect at the time of preliminary approval. In the case of phased projects, upon approval of a final plat for subdivision of the first phase thereof, the applicant shall be given three years to submit final plats for all remaining phases of the subdivision. The three years for submission of the remaining phases may be extended for an additional one-year period upon notification to and approval by the Department, provided that such notification is received at least thirty days before the expiration of the original three-year completion period. Should this period for vesting of rights for the preliminary plat expire, the applicant must then make application for reapproval of the preliminary plat in accordance with all County plans and ordinances in effect at the time of the application for reapproval.