Be default CSV files will be analyzed for duplicates using the default model for the selected target object.

You can change this model after the CSV file is imported.

1) Create an Import (or use an existing one).
2) Navigate to the appropriate Importr Dataset and select the Settings button
3) Change the Matching Model and Press Save.  The existing CSV file will be reanalyzed using the new Matching Model.

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Working with Imported CSV Records