BEGIN
PROMPT Removing DEFAULT value
DECLARE   
   column_ Database_SYS.ColRec;
BEGIN   
   column_ := Database_SYS.Set_Column_Values('COLS9', 'VARCHAR2(10)', 'N','$DEFAULT_NULL$');     
   Database_SYS.Alter_Table_Column('EXAMPLE_TAB', 'M', column_, TRUE);   
END;