In reply to Harald Seifert.

Hi Harald,
I'm not familiar with the ops-util command. Is this a CLI command? I could not find it in the documentation.
As for a REST call to unregister a client, the documentation is here and here is an example call, using curl and deleting the client_id api.client:
curl -k -X DELETE 'https://sasserver.sas.com/SASLogon/oauth/clients/api.client' --header 'Authorization: Bearer eyJhbGciOiJSUzI1NiIsImprdS.........'