Embedded case data is the only kind of data that can be deleted from system tables. An example would be a template. Once a template has been applied to a case, it is embedded within that case. Deleting embedded case data will not affect cases already containing the data, it will only prevent its further usage.
To delete an entry open the appropriate system
table. Double click the entry to be deleted to display the Detail View and
click the Delete button. You can
also delete the entry in List View by highlighting the entry and clicking the
Delete button.