The name of a page is used in various ways throughout a site, and the specific uses depend on the design of the site. In some cases, the name is included in the browser bar title. In other situations, it is used when creating breadcrumb navigation. Within the CMS, the page name is used to label content in the Site Tree and to identify internal links.
You can rename a page at any time, provided that the page is assigned to you. Once an ID has been assigned to a page upon creating the page, changing its name will not break links within the page. Keep in mind that if a site uses structured URLs, renaming the page will change its URL. This could affect external links to the page.
You can rename pages from the Site Tree or from the toolbar.