A few new attributes need to be added to an existing Data Loading (file) import workflow. Is there a way to add fields without rebuilding the entire file format? The 'add' option is greyed out. Only the details on an existing row is available.

For a technical workflow, is there an option or setting to update a schema record except when the import/source field is null - ignore null on import? Example. A recipient record exists with several fields already filled with data. A new import record has some of those fields as empty/null. The expected result is to update that Recipient record without overlaying existing fields with nulls.