CCrmEMail::ResolveResponsibleID

static function ResolveResponsibleID($entityTypeID, $entityID)
{
	$entityTypeID = intval($entityTypeID);
	$entityID = intval($entityID);

	$arFields = self::GetEntity(
		$entityTypeID,
		$entityID,
		array('ASSIGNED_BY_ID', 'CREATED_BY_ID')
	);

	return $arFields ? self::GetResponsibleID($arFields) : 0;
}