Deletes a secure feature key.
sp_drop_secure_feature_key ( name )
You must have EXECUTE privilege on the system procedure. In addition, you must be the database server owner and have the manage_keys feature enabled on the connection.
If the named key does not exist, an error is returned. If the named key exists, it is deleted as long as it is not the last secure feature key that is allowed to manage secure features and secure feature keys. For example, the system secure feature key cannot be dropped until there is another key that has the manage_features and manage_keys secure features enabled.