first, last name user meta

$meta_query = array(
	'relation' => 'OR',
	array(
		'key'     => 'first_name',
		'value'   => 'test',
		'compare' => 'LIKE',
	),
	array(
		'key'     => 'last_name',
		'value'   => 'test',
		'compare' => 'LIKE',
	),
);