A page can be saved at any time. Saving changes does not cause the changes to appear on the published site. Instead, the changes are saved to the copy of the xID.xml page that is stored in a database. 

If there are pending changes that have not been saved, an asterisk appears in the title bar next to the page name. Additionally, the Save button on the toolbar is only available when there are unsaved changes.

To save a page, click Save.