California Code, Public Resources Code - PRC § 30608

No person who has obtained a vested right in a development prior to the effective date of this division or who has obtained a permit from the California Coastal Zone Conservation Commission pursuant to the California Coastal Zone Conservation Act of 1972 (former Division 18 (commencing with Section 27000)) shall be required to secure approval for the development pursuant to this division.  However, no substantial change may be made in the development without prior approval having been obtained under this division.