Sometimes you need to delete the SMP/E data related to one of the systems you are supporting. These are some examples of when you need to delete a zone:

• After a full system generation, you have to delete the information describing the previous target system libraries. Then you rebuild that information to describe the new set of target system libraries built from the distribution libraries.
• After installing a new level of a product that existed in its own target zone and distribution zone, you want to delete the information about the old level of the product and continue processing only the new level.