The Delete History... menu item deletes all or part of
  the library history.  CMS writes the deleted history
  records to a file named HISTORY.DMP in your current
  default directory.

  Delete History... does not delete the library creation
  history record.

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

1  –  Dh db

  The Delete History dialog box allows you to enter
  information about the history you want to delete from the
  library.

1.1  –  Dh bef

  Fill in the Before field with a time value indicating the
  time from which CMS should delete all previous history
  information.

  Entries are made in the history file specifying
  that a section of the history data has been removed. These
  entries are made at the locations in the history file where
  the lines were deleted.

  The time value can be an absolute, delta, or a combination
  time value, or one of the following keywords: TODAY,
  TOMORROW, or YESTERDAY.

1.2  –  Dh obf

  Fill in the Objects field with one or more element names,
  group names, class names, commands, or libraries on which
  you want history deleted. Wildcards are allowed.

  You can specify multiple objects; separate each object
  name with a comma.  This field is optional; if you do not
  supply an object in this field, CMS deletes history
  records for all objects in the current library.

1.3  –  Dh unf

  Fill in the User Name field with the name of one or more
  users to direct CMS to delete the history records created
  by that user.

  You can specify multiple users by separating each user
  name with a comma.

1.4  –  Dh rf

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

1.5  –  Dh of

  The output file directs CMS to write the history output
  you are deleting to the specified file.  If you do not
  supply a file specification for the file, CMS creates a
  file named HISTORY.DMP and places it in your default
  directory.

2  –  Dh tv

  CMS deletes history records based on the transaction
  buttons that are activated.

  Transactions are not deleted for transaction buttons that
  are not activated.

2.1  –  Dhis clear

  Click on the Clear button to deactivate every
  transaction button under Transactions Records
  to Delete.

2.2  –  Dh ct

  When the Copy button is activated, CMS deletes the
  history records of copy transactions.

2.3  –  Dh mt

  When the Modify button is activated, CMS deletes
  the history records of modify transactions.

2.4  –  Dh ut

  When the Unreserve button is activated, CMS deletes
  the history records of unreserve transactions.

2.5  –  Dh mat

  When the Mark button is activated, CMS deletes the
  history records of elements or generations that have been
  marked for review.

2.6  –  Dh cr t

  When the Create button is activated, CMS deletes
  the history records of create transactions.

2.7  –  Dh rem t

  When the Remark button is activated, CMS deletes
  the history records of remark transactions.

2.8  –  Dh vt

  When the Verify button is activated, CMS deletes
  the history records of verify transactions.

2.9  –  Dh rj t

  When the Reject button is activated, CMS deletes
  the history records of elements or generations that have
  been rejected.

2.10  –  Dh dt

  When the Delete button is activated, CMS deletes
  the history records of delete transactions.

2.11  –  Dh rt

  When the Remove button is activated, CMS deletes
  the history records of remove transactions.

2.12  –  Dh se t

  When the Set button is activated, CMS deletes the
  history records of set transactions.

2.13  –  Dh r t

  When the Review button is activated, CMS deletes
  the history records of review transactions.

2.14  –  Dh tvf

  When the Fetch button is activated, CMS deletes the
  history records of fetch transactions.

2.15  –  Dh tvr

  When the Replace button is activated, CMS deletes
  the history records of replace transactions.

2.16  –  Dh at

  When the Accept button is activated, CMS deletes
  the history records of elements whose generations were
  on the review pending list and have been accepted.

2.17  –  Dh tvi

  When the Insert button is activated, CMS deletes
  the history records of insert transactions.

2.18  –  Dh tvr

  When the Reserve button is activated, CMS deletes
  the history records of reserve transactions.

2.19  –  Dh dt

  When the Cancel button is activated, CMS deletes
  the history records of review canceled transactions.