Notify when a colleague is available to talk
If I want to talk to Tim and noticed that his status is set to anything other than "available", e.g. "in a call", then given me an option to click which will remind me the moment Tim's status is changed to "available" again. By this , we do not need to check again and again to see if a colleague is free or busy. I am talking about Carporate Teams desktop client/accounts and not the free app.