The CHANGE GENERIC command modifies a generic element by
    performing a change in place. CDO changes the values you specify,
    and other values remain the same.

    If a generic element is a controlled versioned element, CDO
    freezes previous versions and allows you to modify only the
    highest visible version. If a generic element is an uncontrolled
    versioned element, CDO modifies the highest version unless you
    specify another version number.

    If a generic element is controlled, you must reserve the element
    before you can issue the CHANGE GENERIC command. The SHOW GENERIC
    or SHOW RESERVATIONS command indicates whether this condition
    exists.

    You can modify generic elements that are based on types supplied
    through Oracle CDD/Repository or on user-supplied (extended)
    types. If you do most of your work with extended types, Oracle
    recommends that you should work through the Oracle CDD/Repository
    callable interface. The CDO GENERIC commands are useful to modify
    and display on a spot basis, but extensibility is not supported
    through CDO.

    If you add, change, or delete a property from the generic
    element, the property you specify must be a defined or inherited
    property for the element's type. Likewise, any relationship
    member you specify must be compatible with the relationship
    name's type. See the Oracle CDD/Repository Information Model
    Volume I for more information on valid properties and types.

    If the generic element you are modifying is based on an extended
    type and errors occur when you attempt to add or delete a
    relationship, you may not have specified the processing name
    property as a required property for your type. The property takes
    a quoted string value.

                                 CAUTION

       Specify the MCS_processingName property, not the
       CDD$PROCESSING_NAME property, when you work with extended
       types. Otherwise, you experience performance degradation in
       the Oracle CDD/Repository callable interface.

    The type on which the generic element definition is based
    determines whether an attribute is required or optional in
    instances of the type. If the type definition specifies that the
    CDD$DESCRIPTION attribute can be used in instances of the type,
    you can add documentation text to the generic entity definition
    or remove existing documentation text. You can display text
    entered with the DESCRIPTION clause by using the SHOW GENERIC
    command with the /BRIEF or /FULL qualifiers.

    If the type definition specifies that the CDD$HISTORY_LIST
    relationship can be used in instances of the type, you can
    add explanatory history list entries to the generic entity
    definition. You can display history list entries for generic
    entity definitions by using the SHOW GENERIC command with the
    /AUDIT or /ALL qualifiers.