Use case: In the "Modified by" column, I want to be able to see a catalogers' initials rather than their user ID.
Solution: Add the "modified by" column to the report, select 'edit formula' and enter the following:
REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE("Physical Item Details"."Modified By",'902298925','MH'),'915144202','LF'),'908663101','CDC'),'909413966','MRTL'),'915252914','MKD'),'910061693','CP'),'907604594','YL'),'915628432','HT'),'915802314','ARM'),'909818183','EL')
You can add replacement functions to this by appending ,('USERID','INITIALS') and prepending REPLACE(