<PAGE>

                                                                   EXHIBIT 10.26

                                  DOVEBID, INC.
                                  -------------

                            AMENDMENT TO CONVERTIBLE
                          SUBORDINATED PROMISSORY NOTE

     This Amendment is entered into as of May 8, 2001, by and between Ross J.
Pollack ("Payee") and DoveBid, Inc., a Delaware corporation (the "Company").
This Amendment amends the terms and conditions of that certain Convertible
Subordinated Promissory Note issued by the Company to Payee on March 2, 2000 in
the principal amount of $1,375,000 (the "Note").

     Whereas, Payee and the Company desire to amend the Note on the terms and
conditions set forth below;

     Now, therefore, in consideration of the foregoing and for other good and
valuable consideration (receipt and sufficiency of which is mutually
acknowledged), the parties agree as follows:

     1.   Extension of Term. The paragraph of the Note is hereby amended to read
as follows.

     "DoveBid, Inc., a Delaware corporation (the "Company"), with offices at
     1241 East Hillsdale Blvd., Foster City, CA 94404, for value received,
     promises to pay to the order of Ross J. Pollack ("Payee") at such address
     as Payee may designate, One Million Three Hundred and Seventy Five Thousand
     Dollars and No Cents ($1,375,000), plus simple interest thereon calculated
     from the date hereof until paid at an annual rate of 6.45%, which is equal
     to the minimum rate established pursuant to Section 1274(d) of the Internal
     Revenue Code of 1986, as amended, as of the date hereof, compounded
     annually; provided that if this Note shall not have converted into
     Conversion Stock (as defined below) by March 2, 2003, then on and after
     such date accrued interest with respect to principal then outstanding under
     this Note for each three month period after March 2, 2003 shall be payable
     at the end of each such three month period thereafter. Principal and
     accrued interest will be due and payable in lawful money of the United
     States in full on March 2, 2005 (the "Maturity Date"), unless this Note or
     any portion thereof shall have been previously paid by the Company or
     converted pursuant to Section 2 below, in which case the portion of the
     outstanding principal under this Note that was converted and all accrued
     but unpaid interest thereon shall be satisfied in full by virtue of such
     conversion and the issuance and delivery of fully paid and non-assessable
     shares of Conversion Stock to the holder of this Note as set forth in
     Section 2 below. Payments by the Company shall be applied first to any and
     all accrued interest through the payment date and second to the principal
     remaining due hereunder."

     2.   Definitions.

<PAGE>

          2.1 Definition of Optional Conversion Debt. A new definition is hereby
added to the Note as Section 1.7 to read as follows: " `Optional Convertible
Debt' shall mean $687,500 of the principal amount of this Note (as reduced by
any prepayments made by the Company as permitted in Section 4 hereof), and all
of the accrued but unpaid interest on such portion of this Note."

          2.2 Definition of Mandatory Convertible Debt. A new definition is
hereby added to the Note as Section 1.8 to read as follows: " 'Mandatory
Convertible Debt" shall mean all of the principal amount of this Note and all of
the accrued but unpaid interest on this Note, as reduced by (i) any prepayments
made by the Company as permitted in Section 4 of hereof and (ii) any conversion
pursuant to Section 2.2 of this Note."

          2.3 Definition of Conversion Stock. Section 1.2 of the Note is hereby
amended to read as follows: " 'Conversion Stock' shall mean shares of Common
Stock of the Company, with respect to conversion of the Optional Convertible
Debt, and shall mean Common Stock of the Company of the same class of common
stock that is registered by the Company pursuant to an Initial Public Offering,
with respect to conversion of the Mandatory Convertible Debt. If the outstanding
Common Stock of the Company shall hereafter be changed through a reorganization
or recapitalization into shares of a different series or class of the Company's
capital stock, the Conversion Stock shall thereafter mean the shares into which
the Common Stock was changed."

          2.4 Definition of Conversion Price. Section 1.3 of the Note is hereby
amended to read as follows: "The 'Conversion Price' for Optional Convertible
Debt shall mean $8.01 per share of Conversion Stock, as appropriately adjusted
to reflect the effect of stock splits and combinations, stock dividends,
recapitalizations and reorganizations of or on the Conversion Stock after the
date hereof. For Mandatory Convertible Debt, the `Conversion Price' shall mean
the price per share that is the exact middle of the price range stated in the
Company's final amended registration statement on Form S-1, Form SB-1 or a
similar successor form pertaining to an Initial Public Offering that closes on
or before the Maturity Date. No conversion shall occur and there is therefore no
Conversion Price with respect to an Initial Public Offering that closes after
the Maturity Date."

     3.   Conversion.  Section 2 of the Note is hereby amended to read as
follows:

          "2.1 Mandatory Conversion. This Note and all of the outstanding
     Mandatory Convertible Debt shall be converted into Conversion Stock at the
     Conversion Price immediately prior to the first closing of an Initial
     Public Offering before the Maturity Date. For informational purposes, the
     Company shall provide the Noteholder with written notice (at the most
     recent address for the Noteholder provided to the Company by the Noteholder
     in writing) (i) within seven days after it files with the Securities and
     Exchange Commission any registration statement on Form S-1, Form SB-1 or
     Form SB-2 (or any similar or successor form) for an Initial Public
     Offering, and (ii) reasonably promptly following the closing of an Initial
     Public Offering. Conversion as described in this Section 2.1 shall occur
     only upon the closing of an Initial Public Offering,

                                       2

<PAGE>

     provided that (i) upon the closing of an Initial Public Offering, the
     conversion shall be deemed to have occurred immediately prior to the first
     closing of such Initial Public Offering, and (ii) as a condition precedent
     or condition subsequent to conversion (the election between which type of
     condition shall be the Company's sole election in the Company's sole
     discretion), the Noteholder must surrender this Note for conversion at the
     principal office of the Company. Incident to any conversion, the Conversion
     Stock will have those rights and privileges, and be subject to those
     restrictions, of the shares of Common Stock as set forth in the Company's
     Certificate of Incorporation, and the Noteholder will receive the rights
     and be subject to the obligations applicable to the purchasers of Common
     Stock, provided that the sale restriction specified in Section 2.6 below
     shall apply to the Conversion Stock. This Note shall not be convertible
     pursuant to this Section 2.1 and shall not be converted into Conversion
     Stock under this Section 2.1 if there is not an Initial Public Offering on
     or before the Maturity Date.

          2.2 Optional Conversion. All of the outstanding Optional Convertible
     Debt may be converted, at any time prior to the Maturity Date, into
     Conversion Stock at the Conversion Price in the sole discretion of the
     Company. To elect to convert the Optional Convertible Debt, the Company
     shall send written notice of its election to the Noteholder prior to the
     Maturity Date. Noteholder will thereafter deliver the original Note to the
     Company at the Company's principal office for reissunce to reflect the
     conversion of the Optional Convertible Debt. Incident to any conversion,
     the Conversion Stock will have those rights and privileges, and be subject
     to those restrictions, of the shares of Conversion Stock as set forth in
     the Company's Certificate of Incorporation, and the Noteholder will receive
     the rights and be subject to the obligations applicable to the purchasers
     of Conversion Stock, provided that the sale restriction specified in
     Section 2.6 below shall apply to the Conversion Stock. If the Company fails
     to deliver the written notice provided for in this Section 2.2 prior to the
     Maturity Date, the conversion right of the Company that is set forth in
     this Section 2.2 shall terminate on the Maturity Date.

          2.3 No Fractional Shares. No fractional shares will be issued on
     conversion of this Note. If on any conversion of this Note a fraction of a
     share results, the Company will pay the cash value of that fractional
     share, calculated on the basis of the applicable Conversion Price.

          2.4 Reservation of Stock. Prior to any conversion of this Note
     pursuant to this Section 2 above, the Company will take such corporate
     action and obtain such government consents and approvals as may, in the
     reasonable opinion of its counsel, be necessary to authorize the issuance
     of a sufficient number of shares of Conversion Stock into which this Note
     is to convert.

          2.5 Fully Paid Shares; Certificates. All shares of Conversion Stock
     issued upon the conversion of this Note shall be validly issued, fully paid
     and non-assessable. The certificates representing the shares of Conversion
     Stock

                                       3

<PAGE>

     issued upon conversion hereof shall be delivered to the holder against
     surrender of this Note. The holder, by accepting this Note, undertakes and
     agrees to accept such shares of Conversion Stock in full satisfaction of
     the Optional Convertible Debt or of the Mandatory Convertible Debt, as the
     case may be, that is outstanding as of the effective date of conversion in
     accordance with the terms of this Note. Anything to the contrary in this
     Note notwithstanding, the Company's obligation to issue shares of
     Conversion Stock to any holder of this Note is expressly conditioned upon
     compliance of such issuance with applicable federal and state securities
     laws without registration or other qualification thereunder.

          2.6 Restriction on Sale. Upon and following any conversion pursuant to
     this Section 2, no holder of any Conversion Stock shall effect any sale or
     distribution of any of the Conversion Stock (which shall include any and
     all voting securities received by such holder as or in connection with a
     stock dividend, stock split or other recapitalization or similar
     distribution on or in respect of the Conversion Stock) or any of the
     Company's other equity securities, or of any securities convertible into or
     exchangeable for such securities, during the period beginning on the
     closing of the Initial Public Offering and ending 180 days after such
     closing. The certificate(s) representing the shares of Conversion Stock
     issued upon the conversion of this Note shall be legended to reflect such
     restriction on sale.

          2.7 No Rights or Liabilities as Shareholder. This Note does not by
     itself entitle the Noteholder to any voting rights or other rights as a
     shareholder of the Company. In the absence of conversion of this Note, no
     provisions of this Note, and no enumeration herein of the rights or
     privileges of the holder shall cause such holder to be a shareholder of the
     Company for any purpose by virtue hereof.

          2.8 No Other Conversion. The conversion provisions set forth in this
     Section 2 constitute the sole methods by which this Note will convert."

     4. Effect of Prepayments. There is hereby added an additional sentence at
the end of Section 4 of the Note to read as follows: "In the event of any
partial prepayment of the Note prior to conversion of the entire Optional
Convertible Debt, the amount prepaid shall be credited towards the Optional
Convertible Debt and/or the Mandatory Convertible Debt that does not constitute
the Optional Convertible Debt, as specified by the Company in its sole
discretion, until the Optional Convertible Debt is paid in full."

     5. Effect of Amendment. This Amendment will be effective as of the date
first set forth above, upon execution of this Amendment by the Company and
Payee. This Amendment may be executed in any number of counterparts, each of
which shall be deemed an original and all of which, taken together, will
constitute one and the same Amendment. Except as expressly provided above, the
terms and conditions of the Note remain in full force and effect, unmodified, as
of the date hereof.

                                       4

<PAGE>

     In Witness Whereof, Payee and the Company have executed this Amendment to
Convertible Subordinated Promissory Note, in the case of the Company by a person
duly authorized to do so.

THE COMPANY: DOVEBID, INC.                      PAYEE: ROSS J. POLLACK

By:    /s/ Anthony Capobianco                     /s/ Ross J. Pollack
    -------------------------------------       --------------------------------
                                                (Signature of Payee)
Title: VP and General Counsel
       ----------------------------------

                                       5