You can configure the area settings to determine whether you wish to overwrite matched attributes in cases when only one is allowed per record.

When multiple attributes are allowed per record you can choose whether to always add new attributes, only add if no existing match is found or do not add at all.

You can also specify which attribute settings to match on (description, date and/or comment).

Finally, you have the option to add/update the attribute for only new or existing relationships.