First Amendment to Membership Interest and Asset Purchase Agreement dated November 6, 2017 by and among Resolute Energy Corporation, Hicks Acquisition Company I. Inc., and Resolute Natural Resources Company, LLC as sellers, Resolute Aneth, LLC as the Company, and Elk Petroleum Aneth, LLC as Buyer and Elk Petroleum Limited as Parent Guarantor

Exhibit 2.1

FIRST AMENDMENT TO MEMBERSHIP INTEREST

AND ASSET PURCHASE AGREEMENT

This First Amendment to Membership Interest and Asset Purchase Agreement (this “Amendment”) is made and entered into effective as of November 6, 2017 (“Effective Time”), by and among RESOLUTE ENERGY CORPORATION, a Delaware corporation (“Resolute”), HICKS ACQUISITION COMPANY I, INC., a Delaware corporation (“HACI” and together with Resolute, the “Company Sellers”), RESOLUTE NATURAL RESOURCES COMPANY, LLC, a Delaware limited liability company (“RNR” and together with the Company Sellers, the “Sellers”), RESOLUTE ANETH, LLC, a Delaware limited liability company (the “Company”), ELK PETROLEUM ANETH, LLC, a Delaware limited liability company (“Buyer”), and ELK PETROLEUM LIMITED, an Australian company limited by shares (“Parent Guarantor”).  Buyer, the Company, Sellers and Parent Guarantor are collectively referred to as the “Parties” and individually as a “Party.”

The Parties entered into a Membership Interest and Asset Purchase Agreement dated September 14, 2017 (the “Original MIAPA”) for the purchase and sale of certain Assets, Purchased Assets and Company Units, as such terms are defined therein.  All capitalized terms used herein and not otherwise defined herein shall have the meaning attributed to them in the Original MIAPA.

The Parties desire to amend certain terms of the Original MIAPA as set forth herein.

NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency of which is acknowledged, the Parties agree as follows:

“Parent Guarantor joins this Agreement solely for the purposes of Section 3.04, Article VIII, Section 9.08, Section 11.03, Section 12.05 and Article XIX, and for purposes of such Articles and Sections, Parent Guarantor shall be included as a “Party.””

“(e)Assignment. Effective immediately following the Closing on the Closing Date, Buyer hereby transfers and assigns to Parent Guarantor the obligations of Buyer set forth in Sections 3.04(a), (b) and (c), Parent Guarantor hereby accepts and assumes such obligations, and Sellers hereby consent to such assignment, and thereafter, Buyer shall have no further liability for the obligations set forth in Sections 3.04(a), (b) and (c) and Sellers shall only have recourse against the Parent

Guarantor with respect to such obligations; provided, however, solely for Tax and accounting purposes:

(i)Buyer shall be deemed to initially transfer and assign the obligations under Sections 3.04(a), (b) and (c) to Elk Petroleum, Inc., which shall then be deemed to assign such obligations to Parent Guarantor; and

(ii)any payments of the Additional Consideration shall be reported in the following order: (A) first, as a capital contribution by Parent Guarantor to Elk Petroleum, Inc., (B) second, as a capital contribution by Elk Petroleum, Inc. to Buyer, and (C) third, as a payment by Buyer to Sellers.”

“Section 2.02 Purchased Assets.  On the terms and subject to the conditions herein and the exclusions set forth in Section 2.03, at the Closing, RNR will sell, assign, transfer and deliver to Buyer, and Buyer will purchase, acquire and accept from RNR all of the right, title and interest of RNR in and to the Assets which are owned, leased or licensed by RNR on the Closing Date (the “Purchased Assets”), in each case free and clear of all Encumbrances; provided, however, that the assignment of the Contracts set forth on Annex 1 hereto relating to Operator Services (as defined in the Transition Services Agreement) as reasonably determined by RNR (in its capacity as Operator under the Transition Services Agreement) shall be effective as of and occur upon the completion of the Operations Term (as defined in the Transition Services Agreement).”

“(b) Change of Name. As soon as reasonably possible after the one hundred twenty (120) day period following the Closing (i) Buyer shall change the name of the Company to remove the names of Sellers and their Affiliates or any variations on them, including “Resolute”, and Buyer shall make the requisite filings with, and provide the requisite notices to, the appropriate Governmental Authorities to accomplish the foregoing and (ii) unless prohibited by Governmental Authorities or applicable Laws, Buyer shall remove the names of Sellers and their Affiliates or any variations on them, including “Resolute”, from any signage located in the Aneth Field.”

“(c)subject to Section 2.02, deliver to Buyer possession of the Purchased Assets;”

“(a)deliver to Sellers $147,248,302 of the Purchase Price in immediately available federal funds by wire transfer to the account designated by Sellers in the Closing Statement;”

“No later than three (3) Business Days after the Closing Date, Buyer shall deliver to Sellers $7,228,000, representing the remaining amount of the Purchase Price, in immediately available federal funds by wire transfer to the account designated by Sellers in the Closing Statement.”

“Section 19.08 Replacement of Bonds, Letters of Credit and Guarantees. The Parties understand that none of the bonds, letters of credit and guarantees, if any, posted by the Sellers with Governmental Authorities and relating to the Assets may be transferable to Buyer. No later than December 31, 2017, Buyer shall obtain, or cause to be obtained in the name of Buyer, replacements for such bonds, letters of credit and guarantees, to the extent such replacements are necessary to permit the cancellation of the bonds, letters of credit and guarantees posted by Seller or to consummate the transactions contemplated by this Agreement; provided, however, that on or before the date of Closing, Buyer shall deliver a letter of credit to Kinder Morgan CO2 Company, L.P. as contemplated by that Consent to Assignment dated as of the Effective Time (as defined therein) among RNR, Buyer and Kinder Morgan CO2 Company, L.P.”

“Section 19.12 Notices.  Any notice, communication, request, instruction or other document required or permitted under this Agreement shall be given in writing and delivered in person or by mail, overnight courier service or e-mail (with read receipt requested) to the addresses of Sellers and Buyer set forth below; provided that any notice or report to be delivered to Sellers under Section 3.04 shall be sent to the attention of “Accounting Department.”  Any such notice shall be effective only upon receipt. Notice given by e-mail shall be deemed to have been received by a Party when receipt is confirmed by the applicable transmitting device (with the receiving Party being obligated to respond affirmatively to any read receipt requests delivered by the other Party).”

“A waiver or amendment will be required under the Third Amended and Restated Credit Agreement as a result of the consideration to be paid to Resolute under the Agreement not being comprised of at least 90% cash or cash equivalents and the note to be issued by Buyer constituting an investment for which no basket is available. The waiver or amendment will be obtained by Resolute prior to or simultaneous with Closing.”

[Remainder of page intentionally left blank]

IN WITNESS WHEREOF, the Parties have executed and delivered this Amendment as of the Effective Time.