No modification, amendment or waiver of any provision of this Article XII, nor the consent to any departure by any Subsidiary Guarantor therefrom, shall in any event be effective unless the same shall be in writing and signed by the Trustee, and then such waiver or consent shall be effective only in the specific instance and for the purpose for which given. No notice to or demand on any Subsidiary Guarantor in any case shall entitle any Subsidiary Guarantor to any other or further notice or demand in the same, similar or other circumstances.