Navigate to the page you want to edit and select Edit Page in the Site Actions dropdown list
This will edit a shared version of the page. If you want to edit the page only for your self choose instead personalize page. See https://rasor.wordpress.com/2008/09/06/wss-howto-navigate-a-wss-site/#id.
An text below the header will then tell you: “Version: You are editing the Personal Version of this page“.
More properties: Appearances, Layout and Advanced.
Proberly more to come…