New York Consolidated Laws, Criminal Procedure Law - CPL § 190.15 Grand jury;  duration of term and discharge

1. A term of a superior court for which a grand jury has been impaneled remains in existence at least until and including the opening date of the next term of such court for which a grand jury has been designated.  Upon such date, or within five days preceding it, the court may, upon declaration of both the grand jury and the district attorney that such grand jury has not yet completed or will be unable to complete certain business before it, extend the term of court and the existence of such grand jury to a specified future date, and may subsequently order further extensions for such purpose.

2. At any time when a grand jury is in recess and no other appropriate grand jury is in existence in the county, the court may, upon application of the district attorney or of a defendant held by a local criminal court for the action of a grand jury, order such grand jury reconvened for the purpose of dealing with a matter requiring grand jury action.