Click the gear icon in the header and then click "move". If you're on mobile, it's under the dropdown menu on the right.
Though you can technically do this as many times as you want, it's recommended to only do it when necessary, such as fixing a typo, updating the status, or putting something into the correct format/capitalization. That's because every time you move a page, it leaves a redirect behind, so if you keep moving a page for really trivial reasons you end up with 50 redirects for every page and it all becomes a big mess.
