You can modify the user mapped to the RunAs security role.
If security is enabled, then the Diameter Enabler Web service enterprise applications will have one or more users or groups assigned to the security role, "Diameter_Role." One of these users, or members of these groups, will be mapped to the RunAs role. These settings are normally configured during the installation of the enterprise applications. However, if a different user must be mapped to the RunAs role or if the existing user's password changes, then the enterprise applications settings must be updated to match.
To modify this user ID or password, perform the following steps: