The KOTESOL Bylaws (not Constitution) were amended at the 2014 KOTESOL Annual Business Meeting, but somehow that amendment was never incorporated into the text.
It is now. Bylaws Article X. Amendments.
These Bylaws may be amended by a three-fifths (3/5) majority majority vote of the members present at an ABM, provided that written notice of the proposed changes has been endorsed by at least five (5) members in good standing and has been distributed to all members at least thirty (30) days prior to the vote.
See the CURRENT Constitution and Bylaws at http://koreatesol.org/content/bylaws
Please note that the Conference Program Book does not include this element of the Constitution & Bylaws, but displays the old "two-thirds (2/3) majority" rule. There are no Bylaws amendents before the ABM this year (there is a Constitutional amendment, different set of rules).