Contrary to the defendant's contention, the Supreme Court properly determined that JPMorgan had standing to commence this action. Where, as here, a defendant places standing in issue, the plaintiff must prove its standing in order to be entitled to relief (see U.S. Bank N.A. v Fabbro, 192 A.D.3d 1178, 1178; 21st Mtge. Corp. v Broderick, 191 A.D.3d 744, 746). "A plaintiff has standing in a mortgage foreclosure action when it is the holder or assignee of the underlying note at the time the action is commenced" (U.S. Bank N.A. v Fabbro, 192 A.D.3d at 1179; see Aurora Loan Servs., LLC v Taylor, 25 N.Y.3d 355, 361).