Deleting Data Volumes 
The data of a database is permanently stored in the data volumes (data area). You can delete data volumes to reduce the size of the data area.
The system distributes the data from the deleted data volume throughout the remaining data volumes, deletes the data volume, and then releases the resources that were previously in use. Data volumes of the FILE type are deleted from the file system.
Note
The last data volume cannot be deleted.
Prerequisites
You are logged on to the database as the database system administrator or as a DBM operator with server authorization for accessing database parameters or utility sessions.
More information: Glossary, Server Permission
Procedure
Select the database in the explorer tree.
In the context menu of the database, choose Administration.
Open the Data Area tab page.
Select the volume.
Choose Delete.... .