You need the BI Tool permission to delete a BI Dashboard. However, you can only delete the dashboards that you create, and not those that have been shared with you, unless you made a duplicate of the shared dashboard, which places a copy in your My Items folder.
1. Click Reports in the Navigation Toolbar, and select the BI Toolbox link in the menu.
Dashboards you created include the icon and the shared dashboards you duplicated include the icon.
3. Locate the dashboard you want to delete, and click its icon.
4. Click OK in the confirmation prompt.