How to update existing processes records via import?

Summary:

Dear all,

We need to update a number of frc processes. From the Data Migration tool, we are able to import a file and create new records, but not able to update existing records.

As per the documentation:

it seems like we can use the Data Migration tool to update data:

However, when updating data, the import goes to "Completed" with no errors but the records are not updated.
Is this expected? If yes, can you please suggest a way to achieve this in an easy/fast way?

Content (please ensure you mask any confidential information):

Need a way to update multiple records. This could be needed also in the following scenario: let's suppose we import some new records with the Data Migration tool. Then we realize we made a mistake, like forgot a field or applied a wrong mapping or imported wrong records. In this case we can't adjust or deactivate records anymore rather then entering each records and applying the changes.