EXHIBIT 10.2

FIRST AMENDMENT

TO

PURCHASE AND SALE AGREEMENT

AND JOINT ESCROW INSTRUCTIONS

This FIRST AMENDMENT TO PURCHASE AND SALE AGREEMENT AND JOINT ESCROW
INSTRUCTIONS (this “Amendment”) dated as of December 23, 2005, is made by and
between SP REVERCHON PROPERTIES, LP, a Delaware limited partnership (“Seller”)
and NNN 3500 Maple, LLC, a Delaware limited liability company (“Buyer”), as
successor-in-interest to TRIPLE NET PROPERTIES, LLC, a Virginia limited
liability company.

RECITALS

A. Seller and Buyer entered into that certain Purchase and Sale Agreement and
Joint Escrow Instructions, dated as of October 21, 2005 (the “Agreement”), in
connection with the sale of that certain property located in the City of Dallas,
County of Dallas or the State of Texas, which is commonly known by the street
address of 3500 Maple, Dallas, Texas, as more particularly described in the
Agreement. Capitalized terms used herein and not otherwise defined shall have
the meaning ascribed to them in the Agreement.

B. Buyer and Seller now desire to modify the Agreement.

C. The Agreement has expired and the Seller and Buyer desire to reinstate and
amend the Agreement as hereinafter provided.

NOW THEREFORE, for good and valuable consideration, the receipt and sufficiency
of which is hereby acknowledged, Seller and Buyer do hereby agree that the
Agreement is hereby reinstated and amended as follows:

1. Section 2 of the Agreement is hereby amended by deleting the reference to
“Sixty Seven Million Dollars U.S. ($67,000,000.00)” and replacing it with “Sixty
Six Million Five Hundred Thousand Dollars U.S. ($66,500,000.00)”.

2. Section 6.1 of the Agreement is hereby deleted in its entirety and replaced
with the following”:

“The closing under this Agreement (the “Closing”) shall take place on
December 23, 2005 (“Closing Date”). Buyer shall have the right to elect to
extend the Closing Date to a date not later than December 27, 2005, as set forth
in this Section 6.1. If Buyer elects to extend the Closing Date, Buyer shall, on
or prior to the Closing Date, so notify Seller in writing, and shall deliver to
Seller an additional amount of Seven Hundred Fifty Thousand Dollars U.S. (U.S.
$750,000.00) (the “Third Deposit”). The Third Deposit shall be part of the
Deposit and shall be non-refundable to Buyer except in the event of a default by
Seller which results in the termination of this Agreement, or in the event of
certain casualty or condemnation events as set forth herein.”

3. A new Section 17.13 is added to the Agreement, as follows:

“17.13 Section 3 — 14 Audit.

Seller agrees to cooperate with the Buyer in conjunction with the Section 3-14
audit requirements imposed upon Buyer. Seller’s cooperation is limited to
(i) making its books and records for the calendar year 2004 available for
inspection during normal business hours upon two business days prior notice and
(ii) delivering a “representation letter” in the form attached hereto as Exhibit
“M”. This Section 17.13 shall survive for the six (6) month period after the
Close of Escrow.”

4. A new Exhibit M is added to the Agreement in the form attached hereto as
Exhibit A.

5. All other terms and conditions of the Agreement not specifically modified or
supplemented by this Amendment shall remain unchanged and in full force and
effect, and the Agreement, as supplemented by this Amendment, is hereby ratified
and confirmed. This Amendment (a) shall be governed, construed and enforced
under the laws of the State of Texas, (b) contains the entire understanding of
the parties with respect to the provisions of the Agreement amended and
supplemented hereby, (c) may not be modified except by a writing signed by both
parties and (d) and shall be binding upon and inure to the benefit of Seller and
Buyer, and their respective successors and permitted assigns.

6. In the event of any conflict between the terms of the Agreement and the terms
of this Amendment, the terms of this Amendment shall control.

7. The parties agree that this Amendment may be transmitted between them by
facsimile machine and the parties intend that a faxed Amendment containing
either the original and/or copies of the signature of all parties shall
constitute a binding Amendment. This Amendment may be executed in any number of
counterparts, each of which shall be deemed to be an original agreement and all
of which when taken together shall be deemed to be one and the same agreement.

4.

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IN WITNESS WHEREOF, Buyer and Seller have executed this Amendment as of the date
set forth above.

     
SELLER:
  SP REVERCHON PROPERTIES, LP
a Delaware limited partnership

By: SP REVERCHON OFFICE PROPERTIES GP,

LLC, Delaware limited liability company, its sole

general partner

By: /s/ MICHAEL BURRICHTER

Name: MICHAEL BURRICHTER

Its: VICE PRESIDENT

By: /s/ MING J. LEE

      Name: MING J. LEE

Its: ASSISTANT VICE PRESIDENT

     
BUYER:
  NNN 3500 MAPLE, LLC, a Delaware
limited liability company
 
   
 
  By: Triple Net Properties, LLC,
a Virginia limited liability company, Manager
 
   
 
  By: /s/ LOUIS J. ROGERS
 
   
 
  Name: LOUIS J. ROGERS
 
   
 
  Its: PRESIDENT
 
   
 
   

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