adding a user as fusion administrator

Summary:

Unable to add a user as a Fusion administrator

Content (please ensure you mask any confidential information):

I am trying to add a user as a Fusion administrator in Oracle Console, but I am getting the following error:

"Invalid The Fusion Application administrator cannot be created as user name already exists in Identity Domain"

The user account is already in Identity Domain. How do I get over this error and add the user as one of the Fusion Administrator

Version (include the version you are using, if applicable):

Fusion 25D

Code Snippet (add any code snippets that support your topic, if applicable):