If the original report was not saved before it was scheduled to run, then there will not be a version of it to edit in the Report Writer Reports tab. The recommended best practices when creating a scheduled report is to save the report prior to scheduling it. This can be done during the Review Criteria Step by clicking the Save Report button. You can then Run the report and schedule it as desired.

If you do have a scheduled report that was not saved, you will have to recreate the report to change any of the configurations. You can, though, use the configurations of the original report to recreate it. To do so:
  1. Under the Report Results tab, click View for the latest results of the report.
  2. Select the Report configuration tab. Here you can see a full list of the report configurations.
  3. Depending on the report, you might see a button labeled Edit Report Configuration. You can use this button to reconfigure your report.
  4. If you don't see this button, then you can take a screen shot of the configurations or leave the tab open while recreating the report in a new tab.