<PAGE>
EXHIBIT 99.1(f)
FORM OF
MFS SERIES TRUST IX
CERTIFICATION OF AMENDMENT
TO THE DECLARATION OF TRUST
REDESIGNATION OF SERIES
The undersigned, being a majority of the Trustees of MFS Series Trust
IX (the "Trust"), a Massachusetts business trust organized under the laws of The
Commonwealth of Massachusetts pursuant to an Amended and Restated Declaration of
Trust dated January 18, 1995, as amended (the "Declaration"), acting pursuant to
Section 6.9 of the Declaration, do hereby redesignate an existing series of
Shares (as defined in the Declaration) as follows:
1. The series designated as MFS Mid Cap Value Fund shall be
redesignated as MFS Emerging Opportunities Fund.
Pursuant to Section 6.9(e) of the Declaration, this redesignation of
series of Shares shall be effective upon the execution of a majority of the
Trustees of the Trust.
IN WITNESS WHEREOF, a majority of the Trustees of the Trust have
executed this amendment, in one or more counterparts, all constituting a single
instrument, as an instrument under seal in The Commonwealth of Massachusetts, as
of this ____ day of ________, 2000.
--------------------- --------------------
J. Atwood Ives Arnold D. Scott
17 West Cedar Street 20 Rowes Wharf
Boston, MA 02108 Boston, MA 02110
--------------------- --------------------
Lawrence T. Perera Jeffrey L. Shames
18 Marlborough Street 38 Lake Avenue
Boston, MA 02116 Newton, MA 02159
--------------------- --------------------
William J. Poorvu Elaine R. Smith
975 Memorial Drive 75 Scotch Pine Road
Cambridge, MA 02138 Weston, MA 02193
--------------------- --------------------
Charles W. Schmidt David B. Stone
63 Claypit Hill Road 282 Beacon Street
Wayland, MA 01778 Boston, MA 02116