{
{    The purpose of this request is to return the name of the next variable
{ changed by the terminal user in the form.  The form cannot be pushed.
{
{       FDP$XGET_NEXT_CHANGED_VARIABLE (FORM_IDENTIFIER, VARIABLE_NAME,
{             OCCURRENCE, STATUS)
{
{ FORM_IDENTIFIER: (input)  This parameter specifies the form identifier for
{       the instance of the form.
{
{ VARIABLE_NAME: (output)  This parameter specifies the name of the changed
{       variable.
{
{ OCCURRENCE: (output)  This parameter specifies the occurrence of the variable
{       name.
{
{ CHANGE_FOUND: (output)  This parameter specifies whether a changed variable
{       was found.  If a changed variable was found, change_found equals "T".
{       Otherwise, change_found is equal to "F".
{
{ STATUS: (output)  This parameter specifies the request status.
{
{       CONDITIONS:  fde$bad_data_value
{                    fde$invalid_form_identifier
{                    fde$no_space_available
{                    fde$system_error
{
