You can first get the details of all the systems and then delete a particular system.
curl -k -X GET 'https://<QS_HOSTNAME>:1443/systems' --header 'Authorization: Basic <ADMIN_TOKEN>' curl -k -X DELETE 'https://<QS_HOSTNAME>:1443/systems/<systemName>' \ --header 'Content-Type: application/json' \ --header 'Authorization: Basic <ADMIN_TOKEN>'