This excerpt taken from the CVS 8-K filed Aug 15, 2006.
. Conditions to Defeasance. The Company may exercise its legal defeasance option or its covenant defeasance option only if:
In the case of legal defeasance under this Section 8.02 the Opinion of Counsel referred to in clause (iv)(1) above may be replaced by a ruling directed to the Trustee received from the Internal Revenue Service to the same effect. Before or after a deposit, the Company may make arrangements satisfactory to the Trustee for the redemption of the Debt Securities of such series at a future date in accordance with Article 3.