Section 709. Greater requirement as to quorum and vote of directors

(a) The certificate of incorporation may contain provisions specifying
  either or both of the following:
    (1) That  the  proportion  of directors that shall constitute a quorum
  for the transaction of business or of any  specified  item  of  business
  shall  be  greater than the proportion prescribed by this chapter in the
  absence of such provision.
    (2) That the proportion of votes of directors that shall be  necessary
  for  the  transaction  of  business or of any specified item of business
  shall be greater than the proportion prescribed by this chapter  in  the
  absence of such provision.
    (b) (1) An amendment of the certificate of incorporation which changes
  or strikes out a provision permitted by this section shall be authorized
  at a meeting of shareholders by (A) (i) for any corporation in existence
  on  the effective date of subparagraph (2) of this paragraph, two-thirds
  of the votes of all outstanding shares entitled  to  vote  thereon,  and
  (ii)  for  any  corporation  in  existence on the effective date of this
  clause the certificate of incorporation of which expressly provides such
  and for  any  corporation  incorporated  after  the  effective  date  of
  subparagraph  (2)  of  this  paragraph,  a  majority of the votes of all
  outstanding shares entitled to vote thereon or (B) in either case,  such
  greater  proportion of votes of shares, or votes of a class or series of
  shares,  as  may  be  provided  specifically  in  the   certificate   of
  incorporation for changing or striking out a provision permitted by this
  section.
    (2)  Any  corporation  may  adopt  an  amendment of the certificate of
  incorporation in accordance with any applicable clause or  subclause  of
  subparagraph (1) of this paragraph to provide that any further amendment
  of  the  certificate  of  incorporation  that  changes  or strikes out a
  provision permitted by this section shall be authorized at a meeting  of
  the  shareholders  by a specified proportion of the votes of the shares,
  or particular class or series  of  shares,  entitled  to  vote  thereon,
  provided that such proportion may not be less than a majority.