Change in Class of Section 8 company from private to public

I have a section 8 company which was registered under private class , now the members have increased over 200 , as the private company can have only 200 members now I have to convert the class to section 8 public company. Can anyone give me the procedure for doing it .. The company will be under section 8 company only but due to increased members I have to change its class to public.