Section 45-A. Corporations may conduct business

A  domestic corporation
  desiring or intending to conduct the trade, business  or  calling  of  a
  plumber  or  of plumbing in a city of this state, as employing or master
  plumber, may do so provided one or more  officers  of  such  corporation
  separately  or  aggregately actually hold and own at least fifty-one per
  centum of the issued and outstanding capital stock of said  corporation,
  and  provided  that each of such officers holding such percentage of the
  stock is the holder of a certificate of competency of such board of  the
  city  in  which  it  conducts  or  proposes  to conduct such business as
  provided in section forty-five. In  case  one  or  more  officers  of  a
  corporation  engaged  in  such business shall die, being the holder of a
  certificate of competency, the corporation  may  continue  the  business
  during  the  time  necessarily  required  for  the administration of the
  estate of such deceased  officer,  not  exceeding  two  years  from  the
  granting of letters, provided one or more officers of the corporation is
  the  holder  of  a certificate of competency and together with the legal
  representatives of such deceased officer or officers, actually owns  and
  holds  at  least  fifty-one  per  centum  of  the issued and outstanding
  capital stock of the said corporation. Each and  every  member  of  said
  corporation  holding  a  certificate of competency shall comply with all
  the rules and regulations applicable to master or employing plumbers  in
  the  locality  in  which  the  corporation  is engaged in business. Such
  corporation shall register as provided  in  section  forty-six  of  this
  chapter.