You can reopen previous chats from Activities or from Recents in the left sidebar. Use Activities to view your full chat history, or Recents to open a recent chat directly.
Access Your Full Chat History from Activities
Select Activities in the left sidebar.
Find the chat you want to reopen. Use Type to search... to search the list, or Most Recent to change its order.
Select the chat title to open it.
Open a Recent Chat from the Sidebar
Find Recents in the left sidebar.
Select the chat you want to reopen.
If the chat is not listed under Recents, use Activities to find it in your full chat history.