2020 New York Laws
ELN - Election
Article 5 - Registration and Enrollment of Voters
Title 3 - Enrollment
5-304 - Enrollment; Change of Enrollment or New Enrollment by Previously Registered Voters.

§  5-304.  Enrollment;  change  of  enrollment  or  new  enrollment by
  previously registered voters. 1.  A  registered  voter  may  change  his
  enrollment in the manner prescribed by this section.
2.  The  term  "change of enrollment" shall apply to applications by a
  registered voter already enrolled in one party to enroll in a  different
  party,  or to delete his enrollment in any party, or an application by a
  registered voter not enrolled in any party to  enroll  in  a  particular
  party.
3. A change of enrollment received by the board of elections will take
  effect  immediately, provided however, any change of enrollment received
  by the board of elections after February fourteenth  and  before  or  on
  seven  days  after the June primary shall take effect on the seventh day
  after the June primary.
4. Registered voters may apply for change of enrollment personally  by
  mail  to  or  by  appearing  before  a  county  board of elections or by
  appearing before a board of inspectors. If the applicant has appeared in
  person and if the board finds that he or she is properly registered,  it
  shall   provide  the  applicant  with  an  application  form  for  voter
  registration by mail which shall be treated as an application for change
  of enrollment filed pursuant to this section. If the voter  has  applied
  personally  by mail, the county board of elections shall mail him or her
  an application form for voter registration by mail as provided  by  this
  chapter.   If  a  registered  voter  submits  an  application  form  for
  registration or  enrollment  as  provided  by  this  chapter,  from  the
  residence address from which he or she is then registered, and such form
  reflects  a  change  of  enrollment, the county board of elections shall
  treat such form  as  an  application  for  change  of  enrollment  filed
  pursuant to this section. If such application form also sets forth a new
  address  within  the  same  city or county, the board of elections shall
  also treat such form as an  application  for  transfer  of  registration
  pursuant  to section 5-208 of this article. If a voter has cast a ballot
  in an affidavit ballot envelope on  which  such  voter  claims  a  party
  enrollment  different from the enrollment in the records of the board of
  elections, such affidavit shall be treated as an application for  change
  of enrollment.