I'm finding that over time, the resources originally discovered by adding a device can change (specifically network interfaces, disk volumes etc). The hardware may change for example, but the hostname/IP stays the same. If I re-discover the device, it will find the new resources on the host and allow me to manage them, but I do not have an obvious option to remove the old, now non-existent resource, and often NPM will alert that this dead resource is not responding. I can unmanage the specific item, but this is only for a fixed period of time. If the resource is totally gone, what is the procedure to remove it from a managed device permanently?