Blocking/Unblocking Organizational Units 
Use
You can block organizational units (OUs) by setting the
blocking indicator in the master record of the OU. You can no longer use blocked OUs in subsequent functions. Existing relationships between these OUs and other objects are retained.If you want to release a blocked OU for further use, you can unblock the OU.
Procedure
The Change Organizational Unit: Initial Screen appears.
The Change Organizational Unit: Administrative Data screen appears. Your cursor is positioned on the Description tab page.
You return to the initial screen.