Exhibit 10.1
WAIVER UNDER PURCHASE AND IPO REORGANIZATION AGREEMENT
     Pursuant to Section 9.9 of that certain Purchase and IPO Reorganization
Agreement, dated August 2, 2009 and as amended (the “Agreement”), by and among
Hicks Acquisition Company I, INC., a Delaware corporation (“Buyer”), Resolute
Energy Corporation, a Delaware corporation (“IPO Corp.”), Resolute Subsidiary
Corporation, a Delaware corporation (“Merger Sub”), Resolute Aneth, LLC, a
Delaware limited liability company (“Aneth”), Resolute Holdings, LLC, a Delaware
limited liability company (“Parent”), Resolute Holdings Sub, LLC, a Delaware
limited liability company (“Seller”), HH-HACI, L.P., a Delaware limited
partnership (“Founder”) and certain affiliates of Founder, Parent, Seller, IPO
Corp., Merger Sub and Aneth hereby provide the following waiver that may be
relied upon and enforced by all parties to the Agreement:
WAIVER
     Parent, Seller, IPO Corp., Merger Sub and Aneth hereby waive the condition
to their obligation to consummate the transactions contemplated by the Agreement
stated in Section 7.3(e) of the Agreement but only to the extent that the
Acquisition Consideration is not less than $240,000,000.00.
     IN WITNESS WHEREOF, the parties hereto have executed and delivered this
Waiver this 22nd day of September, 2009.

                          RESOLUTE ENERGY CORPORATION   RESOLUTE HOLDINGS SUB,
LLC    
 
                        By:   /s/ James M. Piccone   By:   /s/ James M. Piccone
                     
 
  Name:   James M. Piccone       Name:   James M. Piccone    
 
  Title:   President       Title:   President    
 
                        RESOLUTE SUBSIDIARY CORPORATION   RESOLUTE HOLDINGS, LLC
   
 
                        By:   /s/ James M. Piccone   By:   /s/ James M. Piccone
                     
 
  Name:   James M. Piccone       Name:   James M. Piccone    
 
  Title:   President       Title:   President    
 
                        RESOLUTE ANETH, LLC                
 
                        By:   /s/ James M. Piccone                              
       
 
  Name:   James M. Piccone                
 
  Title:   President