Manually map department code to department. Anaplan will accept the name or the code and map it correctly.
Ignore department and use a formula instead. PARENT(ITEM('E2 Employees#')). To be honest, this would be my preferred method because you already have the department identified in the lists because department is the parent of the employee. By importing the department manually, you run the risk of being out of sync with the lists and that can cause all kinds of problems later.
If you're just trying to blank out the line item use the formula BLANK and it will remove everything. Then delete the formula.