The Delete Generation... menu item removes information
  about one or more generations of an element. You may want
  to delete some generations of an element if your library
  contains a large number of unneeded generations of an
  element.

  Once a generation is deleted, it cannot be restored to
  its former place in the element in the CMS library.
  You can, however, permanently store the contents of
  the generation using the Archive file button.

  When you choose Delete Generation..., a dialog box
  appears, allowing you to specify options for the
  generation you are deleting.

1  –  Dg cdb

  The Delete Generation dialog box allows you to enter
  information about the generation or generations you want
  to delete from the library.

1.1  –  Dg csf

  If you click on an object or objects before choosing
  the Delete Generation... menu item, the Selected box
  contains those objects.  CMS performs the delete
  transaction on the selected objects.

1.2  –  Dg ef

  Fill in the Element field with the name of one or more
  element expressions to be deleted.

  An element expression can be an element name, a group
  name, a wildcard expression, or a list of these separated
  by commas.

1.3  –  Dg rf

  Fill in the Remark field with text to be associated with
  the transaction and logged in the history file with this
  delete transaction.

1.4  –  Dg ar

  Fill in the Archive File field with the name of a file
  (or files) to which CMS should write all the information
  from the deleted generation.

  If you do not supply a file name, CMS creates a file
  with the same name as the element and the .CMS_ARCHIVE
  file type and places it in your default directory.

1.5  –  Dg ran

  You can choose to delete either a single generation or a
  range of generations using the Single and Range buttons,
  respectively.

1.6  –  Dg si

  Click on the Single button to indicate that you are
  deleting only a single generation of an element.

  By default, CMS deletes the latest generation on the main
  line of descent (1+).  To indicate a specific generation,
  supply the generation number in the Single range field.

1.7  –  Dg rg

  Click on the Range button to indicate that you want to
  delete a sequence of generations of an element.

  If the Range button is activated, you must also specify
  the exact range to be deleted.  Do this by using the From
  or To options.

1.8  –  Dg f

  Click on the From button to specify the start of a range
  of generations that are to be deleted, either including
  or excluding the specified generation. Fill in the From
  field with the appropriate generation number.

  CMS automatically deletes the start of the range including
  the generation you specify unless you click on the
  Exclusive button.

  You must specify the end of the range with the To option.

1.9  –  Dg to

  Click on the To button to specify the end of a range of
  generations that are to be deleted, either including or
  excluding the specified generation. Fill in the To field
  with the appropriate generation number.

  CMS automatically deletes the end of the range including
  the generation you specify unless you click on the
  Exclusive button.

  You must also specify the start of the range with the
  From option.