If the defendant in the action has not timely answered, the plaintiff can submit a default judgment. (CPLR 3215[a]).
After the default judgment is entered, it can be opened or vacated. (CPLR 5015). Within one year of notice of the judgment, it can be vacated on the ground of excusable default, newly discovered evidence, or fraud or misconduct. At any time, no matter how long after the judgment was entered, it can be vacated on the ground of lack of jurisdiction. Improper service of the summons is a common way of establishing lack of jurisdiction. New York City requires process servers to be licensed. If the action was served by an unlicensed process server who should have been licensed, the judgment can be vacated.
A judgment can be vacated if it is based on a usurious loan, such as a merchant cash advance agreement that is a loan for over 25% annual interest.
If the judgment is vacated after the plaintiff has already collected money by enforcing the judgment, the defendant is entitled to a refund, or restitution of the money taken by the plaintiff. This is true even if the judgment was vacated for improper service. Restitution can be requested as part of the motion to vacate the judgment.