2006 New York Code - Bringing In New Parties.

 
    § 62. Bringing in new parties. A lienor who has filed a notice of lien
  after the commencement of an action in a court of record to foreclose or
  enforce a mechanic's lien against real property or a public improvement,
  may  at  any time up to and including the day preceding the day on which
  the trial of such action is commenced, make application upon  notice  to
  the  plaintiff  or  his  attorney  in  such  action,  to be made a party
  therein. Upon good cause shown, the court must order such lienor  to  be
  brought  in  by amendment. If the application is made by any other party
  in said action to make such lienor or other person a  party,  the  court
  may  in  its discretion direct such lienor or other person to be brought
  in by like amendment. The order to be entered on such application  shall
  provide  the  time  for  and  manner  of  serving  the  pleading of such
  additional lienor or other person and shall direct that  the  pleadings,
  papers  and  proceedings  of  the  other several parties in such action,
  shall be deemed amended, so as not to require the making or  serving  of
  papers  other  than  said  order to effectuate such amendment, and shall
  further provide that the allegations in the answer  of  such  additional
  lienor  or other person shall, for the purposes of the action, be deemed
  denied by the other parties therein. The action shall be so conducted by
  the court as not to cause substantially any delay in the trial  thereof.
  The  bringing  in  of  such  additional  lienor or other person shall be
  without prejudice to the proceedings had, and if the action  be  on  the
  calendar  of  the  court,  same  shall retain its place on such calendar
  without the necessity of serving a new note of issue and new notices  of
  trial.