Is there possible way to modify custom post type?

You can change register_post_type() arguments before the new type is created. To do this, use the register_post_type_args filter.

add_filter( 'register_post_type_args', 'se342540_change_post_type_args', 10, 2 );
function se342540_change_post_type_args( $args, $post_name )
{
    if ( $post_name != 'cpt_slug' )
        return $args;

    $args['has_archive'] = true;
    // 
    // other arguments

    return $args;
}