There are two methods for you to close a chat:
Method #1: Hover the mouse pointer over a chat in the chat list and click on the cross.
Method #2: Open a chat and click on the
Close button in the upper left corner.
To close a chat from a mobile device do the following:
Open the chat.
Click on the ellipsis icon in the upper right corner.
You can configure automatic chat closing when a certain amount of time passes after an operator's response in Settings → General.
To learn more, read the Open and closed chats article.