This excerpt taken from the PRE 8-K filed Nov 7, 2006.
. Cancellation. All Securities and Coupons surrendered for payment, redemption, registration of transfer, exchange or conversion or for credit against any sinking fund payment shall, if surrendered to any Person other than the Trustee, be delivered to the Trustee, and any such Securities and Coupons, as well as Securities and Coupons surrendered directly to the Trustee for any such purpose, shall be cancelled promptly by the Trustee. The Company may at any time deliver to the Trustee for cancellation any Securities previously authenticated and delivered hereunder which the Company may have acquired in any manner whatsoever, and all Securities so delivered shall be cancelled promptly by the Trustee. No Securities shall be authenticated in lieu of or in exchange for any Securities cancelled as provided in this Section, except as expressly permitted by or pursuant to this Indenture or the related Series Authorization. All cancelled Securities and Coupons held by the Trustee shall be destroyed by the Trustee, unless by a Company Order the Company directs their return to it.