N.Y. CVP. LAW § 2103 : NY Code - Section 2103: Service of papers

(a)  Who  can  serve.  Except where
  otherwise prescribed by law or order of court, papers may be  served  by
  any person not a party of the age of eighteen years or over.
    (b)  Upon  an  attorney.  Except  where otherwise prescribed by law or
  order of court, papers to be served upon a party  in  a  pending  action
  shall  be  served  upon  the  party's  attorney. Where the same attorney
  appears for two or more parties, only one copy need be served  upon  the
  attorney.  Such service upon an attorney shall be made:
    1. by delivering the paper to the attorney personally; or
    2.  by  mailing the paper to the attorney at the address designated by
  that attorney for that  purpose  or,  if  none  is  designated,  at  the
  attorney's  last  known  address; service by mail shall be complete upon
  mailing; where a period of time prescribed by law is measured  from  the
  service  of  a paper and service is by mail, five days shall be added to
  the prescribed period; or
    3. if the attorney's office is open,  by  leaving  the  paper  with  a
  person  in  charge,  or  if  no  person is in charge, by leaving it in a
  conspicuous  place;  or  if  the  attorney's  office  is  not  open,  by
  depositing  the  paper,  enclosed  in  a  sealed wrapper directed to the
  attorney, in the attorney's office letter drop or box; or
    4. by leaving it at the attorney's residence within the state  with  a
  person  of  suitable  age and discretion. Service upon an attorney shall
  not be made at the attorney's residence unless service at the attorney's
  office cannot be made; or
    5.  by  transmitting  the  paper  to   the   attorney   by   facsimile
  transmission,  provided  that a facsimile telephone number is designated
  by the attorney for that  purpose.  Service  by  facsimile  transmission
  shall  be  complete  upon the receipt by the sender of a signal from the
  equipment of the attorney served indicating that  the  transmission  was
  received,  and  the mailing of a copy of the paper to that attorney. The
  designation of  a  facsimile  telephone  number  in  the  address  block
  subscribed  on  a  paper  served  or filed in the course of an action or
  proceeding shall constitute consent to service by facsimile transmission
  in accordance with this subdivision. An attorney may change or rescind a
  facsimile telephone number by serving a notice on the other parties; or
    6. by dispatching the paper to  the  attorney  by  overnight  delivery
  service  at  the address designated by the attorney for that purpose or,
  if none is designated, at the attorney's last known address. Service  by
  overnight  delivery  service shall be complete upon deposit of the paper
  enclosed in a  properly  addressed  wrapper  into  the  custody  of  the
  overnight  delivery  service for overnight delivery, prior to the latest
  time  designated  by  the  overnight  delivery  service  for   overnight
  delivery.  Where a period of time prescribed by law is measured from the
  service of a paper and service is by overnight  delivery,  one  business
  day  shall  be  added  to  the  prescribed  period.  "Overnight delivery
  service" means any delivery service which regularly  accepts  items  for
  overnight delivery to any address in the state; or
    7. by transmitting the paper to the attorney by electronic means where
  and in the manner authorized by the chief administrator of the courts by
  rule  and,  unless  such rule shall otherwise provide, such transmission
  shall be upon the party's written consent. The  subject  matter  heading
  for  each  paper  sent by electronic means must indicate that the matter
  being transmitted electronically is related to a court proceeding.
    (c) Upon a party. If a party has not appeared by an  attorney  or  the
  party's  attorney cannot be served, service shall be upon the party by a
  method specified in paragraph one, two, four, five or six of subdivision
  (b) of this rule.

    (d) Filing. If a  paper  cannot  be  served  by  any  of  the  methods
  specified in subdivisions (b) and (c), service may be made by filing the
  paper as if it were a paper required to be filed.
    (e)  Parties  to  be  served.  Each paper served on any party shall be
  served on every other party who has appeared, except as otherwise may be
  provided by court order or as provided in section 3012 or in subdivision
  (f) of section 3215. Upon demand by a party, the plaintiff shall  supply
  that  party  with  a  list  of those who have appeared and the names and
  addresses of their attorneys.
    (f) Definitions. For the purposes of this rule:
    1. "Mailing" means the deposit of a paper enclosed in  a  first  class
  postpaid  wrapper,  addressed  to the address designated by a person for
  that purpose or, if none is designated,  at  that  person's  last  known
  address,  in  a  post  office or official depository under the exclusive
  care and custody of the United States Postal Service within the state;
    2. "Electronic means" means any method of transmission of  information
  between  computers or other machines designed for the purpose of sending
  and receiving such transmissions, and  which  allows  the  recipient  to
  reproduce   the   information   transmitted  in  a  tangible  medium  of
  expression;
    3. "Facsimile  transmission"  means  any  method  of  transmission  of
  documents  to  a  facsimile  machine  at  a  remote  location  which can
  automatically produce a tangible copy of such documents.