A motion is an application to the court for a specific court order within the confines of an existing case. A party may amend his pleading once without leave of court within twenty days after its service, or at any time before the period for responding to it expires.This Bloomberg Law Overview describes how parties can amend or supplement pleadings after they have been filed in New York state court. A party may amend his pleading once without leave of court at any time before the period for responding to it expires. A party may move to strike any scandalous or prejudicial matter unnecessarily inserted in a pleading. (c) Time limits; pleading after disposition. A Practice Note explaining key issues counsel should consider when seeking to amend or supplement a pleading in New York state supreme court. While that motion was pending, but over nine months after the Appellate Division order, plaintiff moved for leave to file a third amended complaint. (a) Amendments without leave. I am a Defendant in a lawsuit in Los Angeles, California.