How can a CA IDEAL user be renamed? 

An Ideal user is the key for a PERSON entity in datadictionary which cannot be renamed.

The user will need to be deleted first and then re-added with the new name.

Release : 15.1

Component : CA IDEAL

In CA Idea do the following:

1. Issue the command DISPLAY INDEX USER nnn to see all the records associated with that OPID. 
2. Issue a DEL command for each of the entries in each status associated with that OPID. 
3. Issue the DISPLAY INDEX USER nnn  command repeatedly, entering DEL on the prefix line for each entry, until all the entries are gone.
   Note that even if an entry is in Hist status, it will still hold that relationship. 
4. Once all the entries are gone, issue the CREATE USER command to create the new user.

See documentation section CREATE USER command and  DISPLAY INDEX command