Login and browse to the page that you need to move.
Copy the URL of the browsed page from the browser address bar.
Then browse to the section where you want to put the new link, use Link Manager Existing page Option while creating the link and then past the URL that you had copied.
Once the new link is established, browse back to the original section and then delete that link.
Note :
Moving a page from one section to another just moves the links in the navigation and does not change its breadcrumb or url.
To have a relevant url and breadcrumb, you will have to recreate that page under the new section and re-populate it.