Order::update

protected function update(\Bitrix\Sale\Order $order, array $fields)
{
	$r = new Result();
	$data=[];

	$data['ORDER'] = $fields;
	$data['ORDER']['ID'] = $order->getId();
	$data['ORDER']['PERSON_TYPE_ID'] = $order->getPersonTypeId();

	$orderBuilder = $this->getBuilder();
	$order = $orderBuilder->buildEntityOrder($data);

	if($orderBuilder->getErrorsContainer()->getErrorCollection()->count()>0)
		$r->addErrors($orderBuilder->getErrorsContainer()->getErrors());
	else
		$r->setData(['ORDER'=>$order]);

	return $r;
}