LiveChatManager::checkAvailableName

public function checkAvailableName($alias)
{
	if (!BitrixMainLoader::includeModule("im"))
		return false;

	$alias = self::prepareAlias($alias);
	$orm = BitrixImModelAliasTable::getList(Array(
		'filter' => Array(
			'=ALIAS' => $alias,
			'=ENTITY_TYPE' => BitrixImAlias::ENTITY_TYPE_LIVECHAT,
			'!=ENTITY_ID' => $this->id
		)
	));

	return $orm->fetch()? false: true;
}