With the help of @AlnoorCassim I came up with this:
Put attached file in the ../PR folder and then follow these steps below for the Data tab in the import job:
It has extension M4P but is a text file.
1. Create TEMP field in Data tab, move in front of EMPLOYEE_NO, Operation = Replace and point to EmployeeNo field in source file
2. If field name is other than TEMP01 then edit the m4p file and change the 2 TEMP01 references (e.g. change to TEMP02)
3. Set DEPARMENT_NO to Replace with the correct column - it will be overwritten by the Perform but need valid in there (as you see in PRC dept master) as a placeholder
4. Also in DEPARMENT_NO click Perform button and set like this:
Perform On = A - After Assign
Command = ../PR/PR_Performs.m4p;PR6_SKIP_NONACTIVE