This article explains if an IDEAL User can be renamed and if so, how.
Release : 15.1
Component : CA IDEAL
An Ideal user is the key for a PERSON entity in Datacom Datadictionary which cannot be renamed.
The user will need to be deleted first and then re-added with the new name.
In CICS transaction IDEA to start Ideal ,
See documentation section CREATE USER and DISPLAY INDEX command.