BEGIN
PROMPT Modify LENGTH OF A COLUMN IN EXAMPLE_TAB
DECLARE
   column_ Database_SYS.ColRec;
BEGIN   
   column_ := Database_SYS.Set_Column_Values('COLS1', 'VARCHAR2(50)');   
   Database_SYS.Alter_Table_Column('EXAMPLE_TAB', 'M', column_, TRUE);
END;