[Forums] Excel file upload and append to existing data

I created an initial Entity using the Excel import feature. Which I then went ahead and modified by creating Additonal static entities. E.g. Employee.DepartmentName was changed to Employee.DeptId which points to a static entity, called Department with a Name field.

I now would like to be able to upload and append data to this database from an excel file, which has the original data as Employee.DepartmentName, and it has nothing about the department Id.
How would I go about doing this.