The updated date of the content is displayed on each node with this code in template file.
<?php print strftime( "%Y-%m-%d", $node->changed) ?>
Now when I save the content with admin role the date displayed is the date I updated (of course). But I only want to display the date updated by the author of the content. So how can I prevent admin role from changing "updated date" and only keep the date updated by the content author? Or is there a way to display only the updated date by the author of content?