CEventCalendar::DeleteTrackingUser

function DeleteTrackingUser($userId = false)
{
	if ($userId === false)
	{
		$this->SetTrackingUsers(array());
		return true;
	}

	$arUserIds = $this->GetTrackingUsers();
	$key = array_search($userId, $arUserIds);
	if ($key === false)
		return false;
	array_splice($arUserIds, $key, 1);
	$this->SetTrackingUsers($arUserIds);
	return true;
}