Hicks Acquisition Company I, Inc.

Exhibit 2.1

Xxxxx Acquisition Company I, Inc.

000 Xxxxxxxx Xxxxx, Xxxxx 0000
Xxxxxx, Xxxxx 00000
Fax: (000)000-0000

September 9, 2009

Resolute Holdings, LLC
Resolute Holdings Sub, LLC
Attn: Xxxxx X. Xxxxxxx
0000 Xxxxxxxx Xx.
Xxxxxx, Xxxxxxxx 00000

     Re: Purchase and IPO Reorganization Agreement

     Reference is made to that certain Purchase and IPO Reorganization Agreement (the “Acquisition Agreement”), dated as of August 2, 2009, by and among Xxxxx Acquisition Company I, Inc. (“Buyer”), Resolute Holdings, LLC, Resolute Holdings Sub, LLC (“Seller”), Resolute Aneth, LLC, Resolute Energy Corporation (“IPO Corp.”), Resolute Subsidiary Corporation (“Merger Sub”), and HH-HACI, L.P. (“Founder”). Capitalized terms used herein and not otherwise defined have the meanings assigned to them in the Acquisition Agreement. The undersigned hereby agree as follows:

     Neither Seller nor Buyer shall exercise their rights under Section 9.1(a)(iv) of the Acquisition Agreement at any time prior to October 6, 2009 if the Buyer Stockholder Approval shall have been obtained and the Charter Amendment shall have become effective and in such case, the parties won’t exercise their rights under Section 9.1(a)(iv) of the Acquisition Agreement unless the Closing shall not have occurred by October 6, 2009.

     Notwithstanding Sections 1.5(b), 1.5(c) and 1.6(b) of the Acquisition Agreement requiring (i) the cancellation and forfeiture of 7,335,000 shares of Buyer Common Stock and 4,600,000 Founder’s Warrants held by Founder and (ii) the restriction of 1,865,000 shares of IPO Corp. Common Stock receivable in the Merger in exchange for 1,865,000 shares of Buyer Common Stock held by Founder, the parties hereto hereby acknowledge and agree that such cancellation and forfeiture and such restriction shall be allocated pro rata among Founder and each of Buyer’s independent directors, as reflected on Schedule I hereto.

     The parties hereto acknowledge and agree that except as modified herein, the Acquisition Agreement remains in full force and effect. Please acknowledge your agreement to these terms by signing and returning this letter to the undersigned at the address listed above.

	XXXXX ACQUISITION COMPANY I, INC.
	By:	/s/ Xxxxxx X. Xxxxx
	Name:	Xxxxxx X. Xxxxx
	Title:	President, Chief Executive Officer and Chief
		Financial Officer

Agreed to and Acknowledged:
RESOLUTE ENERGY CORPORATION						RESOLUTE SUBSIDIARY CORPORATION
By:		/s/ Xxxxx X. Xxxxxxx				By:		/s/ Xxxxx X. Xxxxxxx
Name:		Xxxxx X. Xxxxxxx				Name:		Xxxxx X. Xxxxxxx
Title:		President				Title:		President
Date:		9/9/09				Date:		9/9/09
RESOLUTE ANETH, LLC						RESOLUTE HOLDINGS SUB, LLC
By:		/s/ Xxxxx X. Xxxxxxx				By:		/s/ Xxxxx X. Xxxxxxx
Name:		Xxxxx X. Xxxxxxx				Name:		Xxxxx X. Xxxxxxx
Title:		President				Title:		President
Date:		9/9/09				Date:		9/9/09
RESOLUTE HOLDINGS, LLC
By:		/s/ Xxxxx X. Xxxxxxx
Name:		Xxxxx X. Xxxxxxx
Title:		President
Date:		9/9/09

HH-HACI, L.P.
By:		HH-HACI GP LLC, its general partner
By:		/s/ Xxxxxx X. Xxxxx
Name:		Xxxxxx X. Xxxxx
Title:
Date:		9/9/09

Agreed to and Acknowledged, Solely with Respect
to Sections 1.5(b), 1.5(c) and 1.6(b) of the
Acquisition Agreement, as modified by this Letter:

/s/ Xxxxxxx X. Xxxxxxxxxx

Xxxxxxx X. Xxxxxxxxxx

/s/ Xxxxxxx X. Xxxxxxxxxx

Xxxxxxx X. Xxxxxxxxxx

/s/ Xxxxx Xxxxxxxx

Xxxxx Xxxxxxxx

/s/ Xxxxxxx X. Xxxxx

Xxxxxxx X. Xxxxx

Purchase and IPO Reorganization Agreement
Letter Agreement
Signature Page

Schedule I

		Forfeited Common Stock and Warrants / Earnout Shares
		Pre-Closing				Forfeited								Pre-Closing				Forfeited
		Buyer				Buyer Common				Earnout Shares				Founder's				Founder’s
Holder		Common Stock				Stock								Warrants				Warrants
HH-HACI, L.P.			13,524,000				7,188,300				1,827,700				13,524,000				4,508,000
Xxxxxxx X. Xxxxxxxxxx			69,000				36,675				9,325				69,000				23,000
Xxxxxxx X. Xxxxxxxxxx			69,000				36,675				9,325				69,000				23,000
Xxxxx Xxxxxxxx			69,000				36,675				9,325				69,000				23,000
Xxxxxxx X. Xxxxx			69,000				36,675				9,325				69,000				23,000
Total			13,800,000				7,335,000				1,865,000				13,800,000				4,600,000

		Pre and Post-Closing Ownership in Resolute Energy Corporation (“IPO Corp.”)
		Pre-Closing								Post-Closing1
		Buyer				Buyer				IPO Corp.				IPO Corp.				IPO Corp.
Holder		Common Stock				Founder’s Warrants				Common Stock				Earnout Shares				Founders Warrants
HH-HACI, L.P.			13,524,000				13,524,000				4,508,000				1,827,700				9,016,000
Xxxxxxx X. Xxxxxxxxxx			69,000				69,000				23,000				9,325				46,000
Xxxxxxx X. Xxxxxxxxxx			69,000				69,000				23,000				9,325				46,000
Xxxxx Xxxxxxxx			69,000				69,000				23,000				9,325				46,000
Xxxxxxx X. Xxxxx			69,000				69,000				23,000				9,325				46,000

¹ Post-Closing numbers assume none of the holders purchase additional shares of HACI common stock or warrants (in addition to the shares of HACI common stock or warrants issued in connection with the initial public offering of HACI).