It should be a similar way to how you started the call. The Omni's interface changes depending on the user, I believe, so I can't quite tell you what it looks like, aha. [She smiles apologetically, does Chizuru even come from a time with phones... Ciel could hang up first too, but Chizuru wants to and should learn, so she stays on the feed.]

Maybe tap on something that looks like it would end this for you? You can also maybe try to think really hard and make it happen too, since the crystal is attuned to us individually?

[CAN you telepathically shut down a feed? Ciel herself hasn't tried before, but... It's totally a productive experiment to conduct and not a joke to tease the technologically inept girl, really.]