Deleting a realm

You cannot delete a realm that is currently referenced by any other component (such as a job, policy, rule set, group, combo group, or device). You must clear these references manually before the realm can be deleted. When a realm is deleted, all roles that have rights on that realm have those rights removed automatically. Logged events associated with the deleted realm are retained (until aged out) and remain viewable in the Events viewer. The same is true of jobs that ran on the deleted realm; such completed jobs are retained until purged and their detailed results remain viewable.

Do the following:

On the Network > Spans > Realms page, click Delete in the Actions icons for the required realm.