SEO by Yoast: Exclude URLs from canonical

theme-funciont-url-canonical-seobyyoast.php

/* Add this function to the functions.php in your theme folder */
/* to exclude certain posts from url canonicalization of SEO by Yoast plugin */
function wpseo_canonical_exclude( $canonical ) {
		global $post;
		if ( get_post_type( get_the_ID() ) == "name_your_post_type") {
		//if ( $post->ID == 7777) {
    		$canonical = false;
    }
	return $canonical;
}
add_filter( 'wpseo_canonical', 'wpseo_canonical_exclude' );