if( ! function_exists( 'booom_new_portfolio_slug' ) ){
    /**
     * Change the portfolio slug.
     * @param array $args
     * @return array
     */
    function booom_new_portfolio_slug( $args ) {
        $args['labels'] =   array(
            "name" => esc_html__('Galeries','booom'),
            "singular_name" => esc_html__('Galerie','booom')
        );
        $args['rewrite']['slug']    =   'galerie'; // change the slug here.

        return $args;
    }
    add_filter( 'booom/cpt_portfolio/args' , 'booom_new_portfolio_slug', 20, 1 );
}