Synchronizing content and page structures across instances
The import/export tool can be used to synchronize content and page structures between different TYPO3 installations, leaving the content outside the exported page tree unchanged.
Updating content using the TYPO3 backend
To update existing content without creating duplicates, check the option:
Import > Import Options > Update records
This ensures that records with matching UIDs are updated in place.

Update content in an existing structure