loading data from external system leveraging <cn> to derive Core.Name and getting error

Summary:

I have a viewpoint that is getting loaded from an External System. This viewpoint is deriving its Core.Name leveraging a combination of several attributes in the external system's load file. The load file is placing <cn> in its Core.Name column to derive during the load to EDM. This process works as expected when adding nodes. However, if the load file is wanting to update an existing record already in EDM I get an error message that the node.name being derived is already exist in EDM. We expect the node to already exist,