Drupal 6.x Mass update PathAuto Paths Aliases

Change the path in the pathauto settings

goto /admin/content/node in the admin menu under content management -> content.

Filter the nodes as necessary to select the content you want to update.

check the select box at the very top left to check all of the boxes...or individually select the pages

Use the drop down menu to select "update URL Alias" and click update

Do that for each page of nodes, and you're done!