I have a TL-WA1201 access point, and two extenders--an RE215 and an RE315.  As I logged in to change one of the names, I found a third extender, an RE205.  It show up on my network scan with an IP address on my network, and I can ping it.  However, I don't have such an extender, so I of course don't know the admin password.  Complicating matters, I don't have access to my ISP-provided router, so I can't actually block the device by its mac address.

Other than changing the access password on my WAP, is there a way to get this unknown extender off my network?

Thanks.

Bill