How do I leave a chatroom?
Tap the Edit button on the top-left corner of the Chats tab. Then tap the "-" button on the left of the chatroom you want to leave and the "Leave" button will appear.
You can also swipe a chatroom to left from the Chats tab and tap the "Leave" button.
Please note that if you leave a chatroom, the chatroom and its chat history will be permanently deleted.