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PART II. OTHER INFORMATION

Item 6 - (a)                                                         Exhibit 2.4


                   AMENDMENT TO AGREEMENT AND PLAN OF MERGER
                   -----------------------------------------

          AMENDMENT TO AGREEMENT AND PLAN OF MERGER dated as of May 17, 2000
(this "Amendment"), by and between NBT BANCORP INC., a Delaware corporation
("NBT"), and BSB BANCORP, INC., a Delaware corporation ("BSB") (at times,
  ---                                                    ---
referred to herein as the "Party" or the "Parties").
                           -----          -------

                                  BACKGROUND
                                  ----------

          A.   The Parties entered into that certain Agreement and Plan of
Merger dated as of April 19, 2000 (the "Agreement"), pursuant to which BSB will
                                        ---------
be merged with and into NBT, subject to the terms and conditions thereof (the
"Merger").
 ------

          B.   The Agreement provides that the Parties will cause BSB Bank &
Trust Company, a New York-chartered commercial bank and trust company
headquartered in Binghamton, New York and wholly owned subsidiary of BSB ("BSB
                                                                           ---
Bank"), and NBT Bank, National Association, a national banking association
----
headquartered in Norwich, New York and wholly owned subsidiary of NBT ("NBT
                                                                        ---
Bank"), to enter into a bank plan of merger providing for the merger of BSB Bank
----
with and into NBT Bank (the "Bank Merger"), and specifies the Parties' intention
                             -----------
that the Bank Merger be consummated immediately after consummation of the
Merger.

          C.   The Parties now wish to amend the Agreement to specify the
Parties' intention that the Bank Merger be consummated simultaneously with the
consummation of the Merger and to make certain other changes to the Agreement in
connection therewith, and to extend the time for the Parties to determine the
number of directors of the Resulting Bank and for the designation of the
directors of the Resulting Bank by NBT and BSB to no later than 40 Business Days
following the date of the Agreement. Capitalized terms used but not defined
herein shall have the meanings given to them in the Agreement.

          NOW, THEREFORE, in consideration of the foregoing and the mutual
covenants and agreements herein contained, and intending to be legally bound
hereby, the Parties agree as follows:

          1.   Amendment.
               ---------

               (a)  The fourth recital of the Agreement is amended and restated
in its entirety as follows:

                    WHEREAS, prior to consummation of the Merger, NBT and BSB
               will cause BSB Bank & Trust Company, a New York-chartered
               commercial bank and trust company headquartered in Binghamton,
               New York and wholly owned subsidiary of BSB ("BSB Bank"), and NBT
                                                             --------
               Bank, National Association, a national banking association head-
               quartered in Norwich, New York and wholly owned subsidiary of NBT
               ("NBT Bank"), to enter into a bank plan of merger, in the form
                 --------
               attached hereto as Exhibit A (the "Bank Merger Agreement"),
                                  ---------       ---------------------
               providing for the merger of BSB Bank with and into NBT Bank (the
               "Bank Merger"), with NBT Bank being the resulting bank of the
                -----------
               Bank Merger (the "Resulting Bank"), and it is intended that the
                                 --------------
               Bank Merger be consummated simultaneously with consummation of
               the Merger; and

               (b)  Exhibit A to the Agreement is amended and restated in its
entirety in the form attached hereto as Exhibit A.

               (c)  Section 1.07 of the Agreement is amended and restated in its
entirety as follows:


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                    At the Effective Time, the board of directors of the
               Resulting Bank shall consist of the chairman of the board of
               directors of the Surviving Corporation, who shall serve as the
               chairman of the board of the Resulting Bank, and eight, ten or
               twelve other persons, half of whom will be designated by NBT and
               half of whom will be designated by BSB. The number of such other
               persons shall be agreed upon by NBT and BSB, and in the absence
               of timely agreement such number shall be set at ten. The number
               of directors and the selection of directors to be designated by
               NBT and BSB under this paragraph shall be determined and made no
               later than 40 Business Days following the date of this Agreement
               and shall be noted on Schedule 1.07 to be attached to and deemed
               a part of this Agreement, provided, that the president of the
               Resulting Bank shall be one of the directors so designated by
               NBT.

               (d)  Section 2.05(b)(iii) of the Agreement is amended and
restated in its entirety as follows:

                    (iii)   courtesy notice of the Bank Merger to the New York
State Banking Department (the "NYSBD");
                               -----

               (e)  Section 3.05(b)(iii) of the Agreement is amended and
restated in its entirety as follows:

                    (iii)   courtesy notice of the Bank Merger to the NYSBD;

               (f)  Section 8.02 of the Agreement is amended and restated in its
entirety as follows:

          The representations, warranties and agreements in this Agreement shall
terminate at the Effective Time or upon the termination of this Agreement
pursuant to Article VII, except that the agreements set forth in Article I and
in Sections 5.06, 5.07 and 5.08 shall survive the Effective Time indefinitely
and those set forth in Sections 5.03(c), 5.11, 7.02 and Article VIII hereof
shall survive termination indefinitely.

          2.   Representations and Warranties. Each of the Parties hereby
               ------------------------------
represents and warrants to the others as follows:

               (a)  It has the power to execute and deliver this Amendment and
has taken all necessary action to authorize the execution and delivery of this
Amendment and the performance of the Agreement as amended hereby;

               (b)  The execution and delivery of this Amendment and the
performance of the Agreement as amended hereby will not violate any provision of
any applicable law or regulation or of any writ or decree of any court or
governmental instrumentality, or its certificate or articles of incorporation,
by-laws, or other similar organizational documents.

          3.   Reaffirmation. Except as amended hereby, all of the terms,
               -------------
covenants and conditions of the Agreement are ratified, reaffirmed and confirmed
and shall continue in full force and effect as therein written.

          4.   Binding Effect. This Amendment shall be binding upon and inure
               --------------
solely to the benefit of each Party hereto, and nothing in this Amendment,
express or implied, is intended to or shall confer upon any other person any
right, benefit or remedy of any nature whatsoever under of by reason of this
Amendment.

          5.   Counterparts. This Amendment may be executed in one or more
               ------------
counterparts, and by the different Parties hereto in separate counterparts, each
of which when executed shall be deemed to be an original but all of which taken
together shall constitute one and the same agreement.

          6.   Governing Law. This Amendment shall be governed by, and construed
               -------------
in accordance with the laws of the State of Delaware, regardless of the laws
that might otherwise govern under applicable principles of conflicts of law.



          IN WITNESS WHEREOF, NBT and BSB have caused this Amendment to be
executed as of the date first written above by their respective officers
thereunto duly authorized.


<PAGE>

                             NBT BANCORP INC.


                             By:    /s/ Daryl R. Forsythe
                                    -------------------------------------
                             Name:  Daryl R. Forsythe
                             Title: President and Chief Executive Officer

                             BSB BANCORP, INC.


                             By:    /s/ Thomas L. Thorn
                                    --------------------------------------------
                             Name:  Thomas L. Thorn
                             Title: Acting President and Chief Executive Officer


<PAGE>

                                  SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.

                               BSB Bancorp, Inc.



Date:    August 14, 2000                 By: /s/ Thomas L. Thorn
       ---------------------------------     --------------------------------
                                             THOMAS L. THORN
                                             Acting President
                                               and Chief Executive Officer

Date:    August 14, 2000                 By: /s/ Rexford C. Decker
       ---------------------------------     --------------------------------
                                             REXFORD C. DECKER
                                             Senior Vice President
                                               and Chief Financial Officer