Exhibit 99.16

1. Form of Extension Advice

(Telecopy to Tesia Sommer of JPMorgan at 212-270-1063)

Acceptance of Request for Extension

December 22, 2006

Aetna Inc.
151 Farmington Avenue
Hartford, CT 06156

Re: Amended and Restated Five-Year Credit Agreement dated as of January 20, 2006 (the “Credit Agreement”)

Attention: Alfred P. Quirk, Vice President, Finance and Treasurer

Dear Al:

We have received your Extension Request, dated December 5, 2006, and pursuant to Section 2.06(c) (Maturity of Loans) of the above-referenced Credit Agreement, we hereby agree to the extension set forth in such request. Upon the effectiveness of the Extension Request in accordance with Section 2.06(c) of the Credit Agreement, the new Maturity Date will be January 20, 2012.

We have made a notation of this extension on the Schedule of Loans, Payments of Principal attached to our Syndicated Note(s).

Very truly yours,

The Royal Bank of Scotland plc

By: Greenwich Capital Markets, Inc., as agent
By:	/s/ George J. Urban
	Name: George J. Urban
	Title: VP
By:	N/A
	Name:
	Title: