HomePod mini given to new owner: different phone, different network -- no way to connect, or reset

HomePod mini was set up with iPhone A and Network A in room A; it has been given to a different user with iPhone B and network B and room B. The HomePod mini does not responded when iPhone is brought near it. Voice says I'm having trouble connecting to the network, try the Home App. There is no HomePod on the App (new phone;) and clicking + says bring phone close to HomePod, --which does not respond. No way i can find to re-set. The non-removable cord form HomePod has a USB-C at the active end, which my computers do not have the female for. My one USB-C to USB adapter does not light up the HomePod

Any way to re-set by holding buttons, or something simple?