Hi my friends I want to change k2 template (item listing in category) of Gk Music from this
demo.gavick.com/joomla16/nov2011/index.php/2011-08-04-23-47-02/k2-categories/editors-picks
to this TWN 2
demo.gavick.com/joomla16/jul2011/index.php/2011-08-04-23-47-02/k2-user-page

can U guide me how to do this?

If you have both templates installed on your site, you should be able to copy the override file directly from one templates html dierctory to the others, and select it in your category setting (there may be issues with elements and css)