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Exhibit 10.6.d
 
 
Mr. David Nakles
The RETEC Group, Inc.
One Monroeville Center, Suite 1015
Monroeville, PA 15146
 
 
The RETEC Group, Inc.
300 Baker Avenue
Concord, MA  01742
Attn:  President
 
Re:      Modification to that Certain 2005 Modified Agreement
 
Dear Gentlemen:
 
Atlanta Gas Light Company (“AGLC”)  hereby proposes, as set forth below, to make
a modification to the 2005 Modified Agreement between AGLC and Retec, as the
2005 Modified Agreement is identified in that certain letter agreement between
AGLC and Retec attached hereto.
 
 The last paragraph of Section 1 Term is hereby amended by deleting “June 30,
2005” in all three instances in which it appears therein and substituting
therefore in all such three instances “July 31, 2005.”
 
Except as modified herein, all terms, conditions, responsibilities, and
obligations of the Parties set forth in the 2005 Modified Agreement shall remain
in full force and effect. 
 
If you are in agreement with the proposed modifications set forth above, please
so signify by signing on behalf of Retec in the space provided below.  If you
are in agreement, the effective date of the modifications will be June 30, 2005.
 
                                                                                   
Sincerely,
 
                                                                                   
Atlanta Light Company
 
                                                                                   
By: Jeffery Brown
 
                                                                                   
Title: President
 
Agreed and Accepted
 
The Retec Group, Inc.
 
By: Michael D. Knupp
 
Title: President