Properties or child nodes that are marked as mergeable will not be imported by the importer. Instead they will be written into a merge info field of the imported document. This field will be used by the DeskClient to propose those properties and child nodes to be merged manually.
To mark properties or child nodes to be mergeable you can use the attribute merge.
<?xml version="1.0" encoding="UTF-8"?>
<documents xmlns="http://ww.sophoracms.com/import/4.2">
<document externalID="$externalId1$">
<properties>
<property name="sophora-content:headline" merge="true">
<value>The new headline</value>
</property>
</properties>
<childNodes>
<childNode nodeType="sophora-extension-nt:copytext" name="sophora-content:copytext" merge="true">
</properties>
<childNodes>
<childNode nodeType="sophora-extension-nt:paragraph" name="sophora-extension:paragraph">
<properties>
<property name="sophora-extension:style">
<value>headline</value>
</property>
<property name="sophora-extension:text">
<value>...</value>
</property>
</properties>
<childNodes />
<resourceList />
</childNode>
</childNodes>
<resourceList />
</childNode>
<childNode nodeType="sophora-content-nt:storyref" name="sophora-content:teaser" merge="true">
<properties>
<property name="sophora:reference">
<value>eeeed196-343f-4c8a-bbe1-632bb0ef5fa9</value>
</property>
</properties>
<childNodes />
<resourceList />
</childNode>
<childNode nodeType="sophora-content-nt:storyref" name="sophora-content:teaser" merge="true">
<properties>
<property name="sophora:reference">
<value>3ea5af02-b6e3-4609-84f0-1e2b67a357f1</value>
</property>
</properties>
<childNodes />
<resourceList />
</childNode>
</childNodes>
<resourceList />
<fields>
[...]
</fields>
<instructions>
[...]
</instructions>
</document>
</documents>
Note that you can only mark properties, the copytext and component lists (child nodes with a reference type on the document level) to be mergeable.
