SET DATE GERMAN
SET CENTURY ON 

* Проверка работы функции
?F_date(CTOD("21.05.2002"))
?F_date(CTOD("21.12.2002"))

* Сам запрос
SELECT <My_table>.old_date, F_date(<My_table>.old_date) as new_date,;
  ... <возможны другие поля> ;
  FROM <My_table> ;
  INTO CURSOR Q_new_date

FUNCTION F_date
  LPARAMETERS m.old_date
  LOCAL m.new_date
  IF RIGHT(DTOS(m.old_date), 4 ) <= RIGHT(DTOS(DATE()), 4 )
    m.new_date = CTOD(LEFT(DTOC(m.old_date), 6 )+STR(YEAR(DATE()), 4 ))
  ELSE
    m.new_date = CTOD(LEFT(DTOC(m.old_date), 6 )+"2004")
  ENDIF
  RETURN m.new_date
ENDFUNC