Choose the Open submenu item to place a previously
  selected collection, from an active collection view
  window, into the review state.

  The resulting dialog box enables you to choose to be
  either a primary or read-only reviewer. As a primary
  reviewer, only you are able to update benchmarks,
  a procedure that locks the database. As a read-
  only reviewer, you can display the contents of the
  collection; DTM does not lock the database.

  You must use the Open submenu item before you can use
  the Update submenu item and Display functions.