Hi,
You edit default layout, replace
<blocks name="middle" main-inner="1" colwidth="17">
<block name="content-top" style="raw">content-top</block>
<block name="content-bottom" style="raw">content-bot</block>
<block name="content-mass-top" style="raw" type="tabs">ja-news-1,ja-news-2,ja-news-3</block>
<block name="content-mass-bottom">content-mass-bot</block>
<block name="right-mass-top">col-mass-top</block>
<block name="right-mass-bottom">col-mass-bot</block>
<block name="inset1">left</block>
<block name="right1">right1</block>
<block name="right2">right2</block>
</blocks>
with
<blocks name="middle" main-inner="1" colwidth="16">
<block name="content-top" style="raw">content-top</block>
<block name="content-bottom" style="raw">content-bot</block>
<block name="content-mass-top" style="raw" type="tabs">ja-news-1,ja-news-2,ja-news-3</block>
<block name="content-mass-bottom">content-mass-bot</block>
<block name="right-mass-top">col-mass-top</block>
<block name="right-mass-bottom">col-mass-bot</block>
<block name="inset1">left</block>
<block name="right1" width="17">right1</block>
<block name="right2">right2</block>
</blocks>