Ability to manually mark a chat as "resolved", and allow a user to start a new chat conversation on another topic

We can't manually configure chat messages to refresh for the end-user. If someone sends us a message and we solve their problem, there's no way to manually make the chat history clean up/mark it as resolved so they can send us another message. This looks and feels very clunky for the end-user.

The six-hour auto-refresh isn't perfect because conversations can take longer than 6 hours (which would force the chat visitor to restart a chat on the same issue). The chat visitor could also return in under 6 hours in which they can't start a new conversation.