EXHIBIT 10.56.1

                            CHANGE IN TERMS AGREEMENT

     This Change in Terms  Agreement (this "CIT") is made as of and delivered on
April 17,  2008,  by and  between  Mission  West  Properties,  Inc.,  a Maryland
corporation ("Borrower"), and Heritage Bank of Commerce (the "Bank").

                                    Recitals

     A. As of  March  4,  2008,  the  Bank and  Borrower  entered  into  certain
agreements  (the "March  2008 Loan  Documents")  including  but not limited to a
Revolving  Credit Loan  Agreement (the  "Agreement")  pursuant to which the Bank
agreed, subject to the terms and conditions set forth therein, to lend up to the
sum of Ten Million Dollars  ($10,000,000.00) to Borrower,  and pursuant to which
Borrower agreed to repay the loan on or before June 15, 2009.

     B. The Borrower now desires to borrow up to Seventeen  Million Five Hundred
Thousand Dollars and no cents  ($17,500,000.00)  from the Bank from time to time
to meet the working capital needs of the Borrower; and

     C. The Bank is willing to provide such  financing  subject to the terms and
conditions set forth in this Agreement.

     In consideration of the premises and the mutual promises herein  contained,
Borrower and the Bank agree as follows:

                                    Agreement

     1.  INCORPORATION  OF RECITALS.  Each of the  foregoing  Recitals is hereby
incorporated herein by this reference as though set forth in full herein.

     2. COMMITMENT AMOUNT. The definition of "Commitment  Amount" in Section 1.1
of the  Revolving  Credit  Loan  Agreement  is  hereby  replaced  in full by the
following:  "Commitment  Amount"  shall  mean,  as of  any  applicable  date  of
determination,    Seventeen    Million    Five    Hundred    Thousand    Dollars
($17,500,000.00)."

     3. MINIMUM LOAN FEE. The first  sentence in Section  2.9.1 of the Agreement
is hereby deleted and replaced by the following:  "The Borrower shall pay to the
Bank a minimum loan fee of Seventeen Thousand Five Hundred Dollars  ($17,500.00)
(the "Minimum Loan Fee")."

     4. CONDITIONS PRECEDENT. At the Bank's sole and absolute option and for its
benefit,  the  effectiveness  of this CIT and Bank's  obligations  hereunder are
conditioned upon the satisfaction of each and all of the following conditions on
or before April 17, 2008:

          (a)  Borrower  shall  have paid to the Bank the sum of Seven  Thousand
     Five  Hundred  Dollars  ($7,500.00)  in order to bring its  currently  paid
     Minimum Loan Fee of Ten Thousand Dollars to the required total of Seventeen
     Thousand Five Hundred Dollars ($17,500,000.00).

          (b)  Borrower  shall  have paid  one-half  of Bank's  attorneys'  fees
     incurred in  preparing  this  Agreement  and any related  documents  in the
     current estimated sum of Nine Hundred Dollars ($900.00.),  Borrower's share
     Four Hundred Fifty Dollars ($450.00)

          (c) Borrower  shall have executed and delivered to the Bank an Amended
     and  Restated  Revolving  Credit  Note  (the  "Amended  Note")  in the form
     attached hereto as Exhibit A. All references in the Agreement to either the
     "Revolving Credit Note" or the "Note" shall refer to the original Revolving
     Credit Note until such time as Borrower  executes  and delivers the Amended
     Note,  after  which  time  all  references  in the  Revolving  Credit  Loan
     Agreement to either the  "Revolving  Credit Note" or the "Note" shall refer
     to the Amended Note.

          (d) Borrower  shall have provided to the Bank a copy of resolutions of
     the Board of Directors of the Borrower in form  satisfactory to the Bank in
     its sole and absolute discretion  authorizing the execution,  delivery, and
     performance  of this CIT, the  borrowing  hereunder,  and the Amended Note,
     which shall have been certified by the Secretary or Assistant  Secretary of
     the Borrower as of the date of delivery as being complete, accurate, and in
     effect by a certification in the form attached hereto as Exhibit B.

     5. NO OTHER  CHANGES  TO MARCH  2008 LOAN  DOCUMENTS.  Except as  expressly
stated  in  this  CIT  or the  Amended  Note,  there  are no  other  changes  or
modifications to the March 2008 Loan Documents,  and all terms of the March 2008
Loan Documents remain in effect.



<PAGE>


IN  WITNESS  WHEREOF,  the  Borrower  and the Bank  have  caused  this CIT to be
executed by their duly authorized  officers as of the day and year first written
above.

                                         MISSION WEST PROPERTIES, INC.
                                         A Maryland corporation


                                         By: /s/ Raymond V. Marino
                                            ------------------------------------

                                         Print Name: Raymond V. Marino
                                                    ----------------------------

                                         Its:  President & COO
                                             -----------------------------------

                                         HERITAGE BANK OF COMMERCE


                                         By: /s/ Roxanne Vane
                                            ------------------------------------

                                         Its:  Senior Vice President
                                             -----------------------------------



<PAGE>


                   AMENDED AND RESTATED REVOLVING CREDIT NOTE


$17,500,000.00                                              San Jose, California

                                                                  April 17, 2008

     FOR  VALUE  RECEIVED,  the  undersigned  promises  to pay to the  order  of
HERITAGE  BANK OF  COMMERCE  (the  "Bank") at 150 Almaden  Boulevard,  San Jose,
California  (or such other place as Bank may  designate),  on June 15, 2009 (the
"Termination  Date"),  the  principal  sum or so  much of the  principal  sum of
Seventeen  Million Five Hundred  Thousand Dollars  ($17,500,000.00)  as may from
time to time have been advanced and be outstanding  under that certain Revolving
Credit Loan Agreement dated March 4, 2008,  between the undersigned and the Bank
(the  "Agreement")  plus all accrued but unpaid  interest  thereon.  Capitalized
terms used  herein  without  definition  shall have the same  meanings as in the
Agreement.

     The unpaid  principal  amount of this Note shall bear  interest at the rate
provided in the Agreement,  which  Agreement,  as it may be amended from time to
time, is by this reference incorporated herein and made a part hereof.  Interest
shall be  payable to the  extent  accrued  on the first day of each  consecutive
calendar month,  beginning  March 4, 2008,  with all remaining  interest due and
payable on the Termination Date.

     This Note is a Master  Note under  which  sums must be repaid  from time to
time,  and  under  which  Revolving  Loans  may be  made  by the  Bank up to the
Commitment  Amount,  pursuant to the terms and conditions of the Agreement,  and
the books and records of the Bank shall  constitute  prima facie evidence of the
amount of the  Indebtedness  at any time owing hereunder or under the Agreement,
provided,  however, that the failure by the Bank so to record any such amount or
any error in so recording  any such amount  shall not limit or otherwise  affect
the  obligations  of the Borrower  under this Note or the Agreement to repay the
principal  amount  of all the  Revolving  Loans  outstanding  together  with all
interest accrued or accruing thereon.

     The unpaid principal amount of all Revolving Loans,  unless  accelerated in
accordance with the terms of the Agreement,  if not paid sooner, will be due and
payable, together with all accrued and unpaid interest and all other amounts due
and unpaid under the Agreement, on the Termination Date.

     Interest on the  Revolving  Loans is payable in arrears on the first day of
each month during the term of the Agreement  and as set forth in the  Agreement.
The Agreement  provides for the payment by Borrower of various other charges and
fees in addition to interest charges as more fully set forth in the Agreement.

     All  payments of any amount  becoming  due under this Note shall be made in
the manner provided in Section 2.11 of the Agreement.

     Reference is made to the Agreement for, among other things,  the conditions
under  which  this  Note may or must be paid in  whole  or in part  prior to the
Termination Date (whether accelerated or otherwise).

     If an Event of  Default  (as  defined in the  Agreement)  occurs and is not
cured within the time provided for by the  Agreement,  the Bank may exercise any
one or more of the rights and  remedies  granted by the  Agreement or any of the
Loan Documents or available under  applicable law,  including  without limit the
right to accelerate this Note or the  Indebtedness,  and may set off against the
principal of and interest on this Note or against any other Indebtedness (i) any
amount  owing  by  the  Bank  to  the  undersigned,  (ii)  any  property  of the
undersigned  at any time in the possession of the Bank or any Affiliate (as that
term is  defined  in the  Agreement)  of the Bank and  (iii)  any  amount in any
deposit or other  account  (including  without  limit an account  evidenced by a
certificate of deposit) of the undersigned with the Bank or any Affiliate of the
Bank.

     The  undersigned  and its  successors  and assigns  and all  accommodations
parties,  guarantors and endorsers (i) waive  presentment,  demand,  protest and
notice  of  dishonor,  (ii)  agree  that  no  extension  or  indulgence  to  the
undersigned  or  release or  non-enforcement  of any  security,  with or without
notice,  shall affect the obligations of any accommodation  party,  guarantor or
endorser,  and (iii) agree to reimburse  the holder of this Note for any and all
costs and expenses  incurred in  collecting or attempting to collect any and all
principal  and interest  under this Note  (including,  but not limited to, court
costs and attorney fees, whether in-house or outside counsel is used and whether
such costs and expenses are incurred in formal or informal  collection  actions,
federal bankruptcy proceedings,  appellate proceedings,  probate proceedings, or
otherwise,  all as more  specifically  set forth in Sections  8.7 and 8.8 of the
Agreement).  This Note shall be governed by and construed in accordance with the
laws of the State of California.


<PAGE>


IN WITNESS WHEREOF, this Note has been delivered and accepted at Cupertino,
California and the undersigned has executed this Note as of the 17th day of
April, 2008.

                                            MISSION WEST PROPERTIES, INC.
                                            A Maryland corporation


                                            By: /s/ Raymond V. Marino
                                               ---------------------------------

                                           Print Name: Raymond V. Marino
                                                      --------------------------

                                           Its: President & COO
                                               ---------------------------------