您可以使用wp_update_post() 更改帖子的状态。

global $current_user;
get_currentuserinfo();

$post_id = $_GET[\'post_id\'];
$the_post = get_post( $post_id );

if ( $the_post->post_author == $current_user->ID && $the_post ) {
    $the_post->post_status = \'draft\';
    wp_update_post( $the_post );    
}