
{    The purpose of this routine is to change the NAD status unit
{    request so that the PP will unconditionally obtain the local
{    NAD status.  This request is used at shut-down time to force
{    the termination of the request.  This request is also used
{    when the system task has not received any NAD status within
{    a threshold.
{
{    unit_number: (input) This parameter specifies the logical unit
{      number of the corresponding local NAD.
