Unpair Homekit device from Home Assistant

I set up a Homekit device using the iOS app, pairing it with my Apple Homekit account and testing some of the functions. Then I unpaired from my Homekit account and re-paired it with Home Assistant (as required). Works fine, except for one function that isn’t supported In Home Assistant that I didn’t get a chance to test.

So now I want to unpair it from Home Assistant so I can re-pair it with Homekit. But I don’t know how to do that. Apparently deleting the auto-discovered entity in Home Assistant doesn’t actually delete it, and even if it did that wouldn’t unpair it.

So how can I ever unpair my Homekit device from Home Assistant??