Perform the following steps to modify a data class.

1. Display the Data Class Application Selection panel (select option 4 from the ISMF Primary Option Menu for storage administrators).

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2. Supply values on the Data Class Application Selection panel:

   CDS Name

   Is the name of the SCDS that contains the data class you want to change.

   Data Class Name

   Is the name of the data class.

   Option

   Select option 4, Alter. This displays the Data Class Alter panel. This panel contains the same attributes as the Data Class Define panel. The fields are primed with the information that you entered when you defined the data class.

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3. Type over the old information with your new information on the Data Class Alter panel. For more information, see Defining data class attributes.

   Use the DOWN command to see the next page.

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4. Use the END command to save the changes and return to the Data Class Application Selection panel.

In addition, page 1 of this panel allows storage administrators to specify a value for the Additional Volume Amount attribute. Additional Volume Amount is applicable only to extended format VSAM multivolume data sets. Additional Volume Amount is specified when Data Set Name Type = EXT and Volume Count>1. The valid values for this attribute are 'P' (primary), 'S' (secondary), and blank (not specified; the system default is primary).

For descriptions of the attributes contained in the Data Class Alter and the Data Class Define panels, see Defining VSAM attributes and specifying media types for data class.