Code:
// Per-Page meta-tags. Follow this pattern for individual pages you wish to override. This is useful mainly for additional pages.
// replace "page_name" with the UPPERCASE name of your main_page= value, such as ABOUT_US or SHIPPINGINFO etc.
// repeat pattern as necessary
  define('META_TAG_DESCRIPTION_page_name','');
  define('META_TAG_KEYWORDS_PAGE_page_name','');
  define('META_TAG_TITLE_PAGE_page_name', '');
You can set them per page with this code.