Section 26. Extension of lines

A  telegraph  corporation,  a telephone
  corporation or a  telegraph  and  telephone  corporation  heretofore  or
  hereafter  incorporated  under  or  by  any  general  or special law may
  construct, own, use and maintain  any  line  of  electric  telegraph  or
  telephone,  whether  or  not  the  line and the territory in which it be
  located was described in its original certificate of incorporation,  and
  whether  wholly  within  or  wholly or partly without the state, and may
  join with any other corporation in constructing, leasing, owning,  using
  and  maintaining  such  line,  or  hold  or own any interest therein, or
  become lessees thereof, upon delivering to the department of  state  for
  filing  a  certificate of amendment. If the lines or territory are to be
  extended the certificate shall  describe  the  territory  in  which  the
  operations of the corporation are to be carried on.