Regenerate a campaign
Once a campaign is created, the settings you have configured by that point will have effect on the newly created campaign. If you change your settings afterwards (i.e. switch to a different URL shortener, change the content on your blog post...) these changes will not be applied to your campaign. This is where the regenerate option comes in handy.
You can access it from the created campaigns page:

Active and paused campaigns can only be cancelled and re-created from the Cancelled tab.