You can fine-tune one chat on its own without changing your organization-wide defaults.
Open any group, site, category, opportunity, shift, or database-wide chat. For admins, a gear icon appears in the chat header. It opens a Chat settings panel for that one chat.
No. Changes here take effect immediately for that chat.
The per-chat settings are for admins only. The gear does not appear on one-on-one direct messages.