Ignores all page changes since the last COMMIT or last ROLLBACK
    command. Altered pages are stored in virtual memory until you
    issue a COMMIT or a ROLLBACK command. The ROLLBACK command tells
    RdbALTER to ignore all changes since the last COMMIT or the last
    ROLLBACK command was issued.

    Do not follow a ROLLBACK command with a DEPOSIT command without
    first specifying your location again with a DISPLAY or a PAGE
    command.

    RdbALTER does not allow you to issue an EXIT command until all
    altered pages are either committed or rolled back.