This article will show you how to change the assigned user to incase the user is no longer working in your office but still has matters assinged to him/her.
Very simple just go to the a matter you know that user is assinged too. Selec the "i" icon next to the matter title.
Once selected, select Edit. Also from this page you can see who the matter is assinged too.
After you select Edit a new window will appear. Select on the drop down in the assigned too section and select a new user to own the matter.
Do this to all matter that are deemed necessary.