N.Y. Real Property Actions & Proceedings Law § 1315

§ 1315. Action by owner of junior participating interest. An action\nmay be maintained by the owner of a junior participating share or\ninterest in a bond or note secured by a mortgage on real, or on real and\npersonal property, for the payment of principal and interest and for\nforeclosure of such bond or note and mortgage in its entirety, or in the\nalternative, subject to the interest of the owner of the senior share,\nnotwithstanding that the entire mortgage debt may be due and payable\naccording to its terms, in the event that the owner of the senior share,\nto whom is given the right in the participating agreement to enforce\nsuch bond or note and mortgage shall fail or refuse to commence an\naction for the enforcement of such bond or note and mortgage in any\nmanner permitted thereby, after ten days' written notice and demand to\ncommence any such action, following default in the performance of any of\nthe terms and covenants of such bond or note and mortgage. Upon such\nfailure or refusal, such junior participant may exercise any and all\noptions and remedies provided in such bond or note and mortgage or\notherwise available to any holder thereof.\n