Drupal: Change the URL for a Page

Step-by-step guide

CAUTION: Editing a URL Alias incorrectly may disable your web page. Make these changes with extreme caution.

When you edit a page in Drupal, there is a section at the bottom called URL path settings.
To change the page URL, uncheck the box for Generate automatic URL alias so that you edit the URL alias field.
Change ONLY the URL part after the path, i.e., the page title. Do not add spaces or other punctuation, only letters, numbers and hyphens.
Save and Publish. This will create a redirect from the old path to the new URL.