How to update only a specific value of a multiple property?

Question

1C-Bitrix

Hello. At once I will tell, to dock read, but logic did not understand.
There is an array of values ​​of a multiple property of type string. I need to change the description of one of them. I do it like this:

$PROPERTY_VALUE = array(
                            $propNumber => array("VALUE"=>$articleId,"DESCRIPTION"=>""),
                              );
 CIBlockElement::SetPropertyValuesEx($arFields['ID'], 19, array($propNameKey => $PROPERTY_VALUE));

where $propNumber is the property value key in the VALUES array. But in this way, all VALUES is cleared for me, and only one of my values ​​\u200b\u200bis added.

Answer 1

Faced with it. Solutions other than how to read the previous value first, and then overwrite it by adding it to the list, I did not find it.