[themes] Regions in different templates .

Hi, I've got a question about region in templates,. Can I remove region in templates after that they are already in page.tpl.php ? Example I have regions in my page.tpl.php [header] [main] [footer] and now can I remove the [main] region totaly in page--about.tpl.php template when he is used ? or change it to example [left_sidebar] ? ofcourse all my regions are sets already in .info file Does it make any errors ? Thx BR>