This chapter shall not apply to any individuals or groups of individuals within this state who prior to the passage of this chapter were permitted to organize a corporation and perform personal services to the public by means of a corporation, and this chapter shall not apply to any corporation organized by such individual or group of individuals prior to the passage of this chapter: PROVIDED, That any such individual or group of individuals or any such corporation may bring themselves and such corporation within the provisions of this chapter by amending the articles of incorporation in such a manner so as to be consistent with all the provisions of this chapter and by affirmatively stating in the amended articles of incorporation that the shareholders have elected to bring the corporation within the provisions of this chapter.