2010 New York Code
RPP - Real Property
Article 9 - (290 - 336) RECORDING INSTRUMENTS AFFECTING REAL PROPERTY
291-CC - Recording modifications of leases.

§  291-cc.  1.  Recording  modifications  of  leases. Where a lease or
  memorandum of such lease has  been  recorded,  an  unrecorded  agreement
  modifying  such  lease  or  memorandum  is  void as against a subsequent
  purchaser in good faith  and  for  a  valuable  consideration,  and  the
  possession of the tenant shall not be deemed notice of the modification,
  unless the agreement of modification or a memorandum thereof is recorded
  prior  to  the  recording  of  the  instrument  by  which the subsequent
  purchaser acquires his estate or interest.
    2. A memorandum of an agreement modifying a  lease  shall  contain  at
  least the following information with respect to the agreement: the names
  of  the parties and the addresses, if any, set forth in the agreement; a
  reference  to  the  agreement  with  its  date  of  execution;  a  brief
  description  of  the  leased premises in form sufficient to identify the
  same; any changes made by the agreement in the term of the lease and the
  date of the termination of the lease as modified, and any changes in the
  provisions of the lease as to the rights of extension or renewal.
    3. For the purpose of this section the  word  "purchaser"  includes  a
  person who purchases or acquires by exchange or contracts to purchase or
  acquire  by  exchange  the leased premises or the real property of which
  the leased premises are part or  any  estate  or  interest  therein,  or
  acquires by assignment the rent to accrue from tenancies or subtenancies
  thereof in existence at the time of the assignment.