CPLR R. 3216(b)(3) & CPLR § 2004

(3)
The court or party seeking such relief, as the case may be, shall have
served a written demand by registered or certified mail requiring the
party against whom such relief is sought to resume prosecution of the
action and to serve and file a note of issue within ninety days after
receipt of such demand, and further stating that the default by the
party upon whom such notice is served in complying with such demand
within said ninety day period will serve as a basis for a motion by the
party serving said demand for dismissal as against him for unreasonably
neglecting to proceed.

CPLR § 2004 Extensions of time generally

Foley v West-herr Automotive Group, Inc., 2009 NY Slip Op 04808 (App. Div., 4th, 2009)

Supreme Court did not abuse its discretion in denying the motion of
plaintiffs seeking permission to conduct further discovery and to
vacate the court's demand to serve and file a note of issue pursuant to
CPLR 3216 (b) (3) within 90 days. The court's demand provided that, in
the event that plaintiffs failed to comply with the demand, the court
upon its own motion would dismiss the complaint based on plaintiffs'
unreasonable neglect in proceeding with the action. We note that
plaintiffs moved within the 90-day period to vacate the demand and for
an extension of time in which to complete discovery, thereby avoiding
default with respect to the court's demand (see Walton v Clifton Springs Hosp. & Clinic, 255 AD2d 964, 965; Conway v Brooklyn Union Gas Co., 212 AD2d 497; cf. Baczkowski v Collins Constr. Co.,
89 NY2d 499, 503-504). We further note, however, that "[t]he motion
requires the moving party to make a showing of need for the extension
or good excuse for past delay" (Walton, 255 AD2d at 965 [internal quotation marks omitted]; see CPLR 2004; Cook v City of New York, 11 AD3d 424).
We conclude that plaintiffs failed to demonstrate good cause for an
extension of time in which to complete discovery, and they also failed
to present a good excuse for the delay. Plaintiffs sought to excuse the
prior delay by showing that the court's discovery deadline was
ineffective, in view of the parties' continued discovery and the
determination of an appeal after that deadline had expired. However,
the record does not support the conclusion that the court's demand
pursuant to CPLR 3216 (b) (3) was based upon plaintiffs' violation of
its discovery deadline, as opposed to the failure of plaintiffs to move
the case forward after the discovery deadline had expired. We therefore
conclude that the court did not abuse its discretion in denying the
motion. We note in any event that the order denying plaintiffs' motion
further [*2]extended the time in which to
file a note of issue and statement of readiness beyond the original
90-day deadline in the demand, and it specified that, in the event that
plaintiffs did not comply with that later deadline, the court's motion
to dismiss the complaint would be "heard" on such later date. Thus, the
order in effect gave plaintiffs yet another extension of time in which
to complete discovery.