You can access additional options about a chat, by taping

at the top
right corner of the specific chat screen.
From there you can select one
of the following options:
- Call
Start an audio call with other chat
participants.
- Video Call (available only for one-to-one
chats)
Start a video call with the other chat
participant.
- E-mail
Send an email to the chat
participants.
-
Leave Chat (available only for group
chats)
Leave the group chat conversation.