Follow these steps:
- Go to Pure: https://pure.knaw.nl
- Go to Master data and click on External Persons.
- Under External Persons click Duplicate Names and Duplicate ID.
- Check the list of duplicate names.
- By clicking the External Persons you can go the External Person record.
- In the record click on the history and comments to see the external person to which institute belongs.
- Decide which record should be set as target.
- Click on Set as target, Preview merge, and Merge.