Change the level on the checkout page

Woocommerce + constant contact checkbox levl

function connormagyar_override_ctct_label( $args, $key, $value ) {
	if ( 'customer_newsletter_opt_in' !== $key ) {
		return $args;
	}

	$args['label'] = 'SOME CUSTOM LABEL';

	return $args;
}
add_filter( 'woocommerce_form_field_args', 'connormagyar_override_ctct_label', 10, 3 );