When you delete scenarios, all planning units that use the scenario (including data) are deleted. You cannot delete scenarios used in planning units that are started, or assigned to an axis on a form. You must first remove references to scenarios from forms and assign different scenarios.
To delete scenarios:
Select Administration, then Manage, then Dimensions.
Select Scenarios.
Select the scenarios to delete. At least one scenario must remain in the application.
Click Delete.
Click OK.
Update and validate business rules and reports.