Call::getChildCalls

static function getChildCalls($callId)
{
	$cursor = CallTable::getList([
		'select' => ['CALL_ID'],
		'filter' => [
			'=PARENT_CALL_ID' => $callId
		]
	]);

	$result = [];
	while ($row = $cursor->fetch())
	{
		$result[] = $row['CALL_ID'];
	}
	return $result;
}