Corp. Code, § 909

A corporation formed for a limited period may at any time subsequent to the expiration of the term of its corporate existence, if it has continuously acted as a corporation and done business as such, extend the term of its existence by an amendment to its articles removing any provision limiting the term of its existence and providing for perpetual existence. If the filing of the certificate of amendment providing for perpetual existence would be prohibited if it were original articles by the provisions of Section 201, the Secretary of State shall not file such certificate unless by the same or a concurrently filed certificate of amendment the articles of such corporation are amended to adopt a new available name. For the purpose of the adoption of any such amendment, persons who have been functioning as directors of such corporation shall be considered to have been validly elected even though their election may have occurred after the expiration of the original term of the corporate existence. The certificate of amendment shall set forth that the corporation continuously acted as a corporation and did business as such from the expiration of its term of corporate existence to the date of the amendment.