Variables allow you to define a global setting to be used across all pages in your site. This allows you to update the variable in one place rather than on each page of your site. However, you may wish to make a change to these global settings on a specific page. You make such a change by overriding a variable.
You can choose to override a variable on a specific page and create a unique setting for that page only. To do so, use the "Override Variable" button at the top of the Edit page, accessed by navigating to the page you wish to edit and clicking the Edit button in the Editor toolbar.
To set up a Variable Override:
To undo an override, so that the item page is restored to the global variable again, edit the item again and click "Undo Override". You'll see a list of variables currently "overridden" for that item. Choose one, click [Update\, and the item will lose its unique setting and will default to your standard Item page look.