The same guidelines about copying an entire guide apply regarding getting permission to borrow someone else's page.
The second link in the Command Bar under "Add/Edit Pages" is used to ""Reuse Existing Page"
You can make an exact copy of another page in the system (create an exact copy), OR you can create a "linked" copy of another page (create a linked page). A "linked" page will display the information from another page but you will not be able to make any changes to it. Every time the original (source) page is changed, your linked page will automatically update as well.