Go to Favorites > Families (Basic) > select and edit the appropriate family. PRO TIP! Remember you can search in a variety of ways for your family's in the upper-right search menu.
Click Update Overrides & Account Title.
You may edit Family Name Override, Family Greeting Primary Override, Family Greeting All Override, or Account title. Click Save and Back when you are done. (Right-click and 'Open image in new tab' to enlarge)