law: Chartered Accountants Act, 1949 
  13. Resignation of membership and casual vacancies
  (1) Any member of the Council may at any time resign his
  
  membership by writing under his hand addressed to the President, and the seat
  
  of such member shall become vacant when such resignation is notified in the
  
  Official Gazette.
  (2) A member of the Council shall be deemed to have vacated his
  
  se at if he is declared by the Council to have been absent without sufficient
  
  excuse from three consecutive meetings of the Council, or if his name is, for
  
  any cause, removed from the Register under the provisions of section 20.
  (3) A casual vacancy in the Council shall be filled by fresh
  
  election from the constituency concerned or by nomination by the Central
  
  Government, as the case may be, and the person elected or nominated to fill the
  
  vacancy shall hold office until the dissolution of the Council:
  PROVIDED  that no election shall be held to fill a
  
  casual vacancy occurring within six months prior to the date of the expiration
  
  of the duration of the Council, but such a vacancy may be filled by nomination
  
  by the Central Government after consultation with the President of the Council.
  
  
  (4) No act done by the Council shall be called in question on
  
  the ground merely of the existence of any vacancy in, or defect in the
  
  constitution of, the Council.