Deleting IIR Relationships
Unwanted Includes, Imports, and Redefines can be deleted in a Design window. If a given relation cannot be deleted, a message box pops up stating the reason of and offering a solution for the failure.
To delete an IIR relation:
1.Do one of the following:
•Right-click an IIR connector line and select Delete from the context menu.
•Select an IIR connector line and press the Delete key.
•Select an IIR connector line and click the Delete 
button in the Standard toolbar.
A message box appears asking whether you really want to delete the selected objects.
2.To confirm the deletion, click Yes.