2006 New York Code - Defendants.

 
    §  631.  Defendants.  Where  the  complaint  demands  judgment for the
  immediate possession of  the  property,  if  the  property  is  actually
  occupied,  the  occupant shall be made defendant in the action. If it is
  not so occupied,  the  action  shall  be  brought  against  some  person
  exercising  acts of ownership thereupon, or claiming title thereto or an
  interest therein, at the time of the commencement  of  the  action.  Any
  person  claiming  title  to, or the right to the possession of, the real
  property sought to be recovered, as landlord, remainderman, reversioner,
  or otherwise adversely to the plaintiff, may be joined as defendant.