To disconnect Pipedrive from a Scenario and remove all the data it contains, select the Pipedrive icon to the right of the Scenario name. It will bring up a menu that shows all the Scenario Import Settings and date ranges.
Simply click on Disconnect in red and hit OK when prompted. All of your Pipedrive data and settings will be removed.
Note: Be aware that any manually created items that are in a Category that has been imported from Pipedrive will be deleted along with any information that has been imported into that Scenario or Forecast. Make sure you have moved any manually created items into a separate Category.