Changes the value in a field in one or more records from a
    relation or open stream. Before you use the MODIFY statement,
    you must start a read/write transaction and establish a record
    stream with a FOR statement or a START_STREAM statement. The
    context variables you refer to in MODIFY statement must be the
    same as those defined in the FOR or START_STREAM statement.

    Example:

    RDO>  FOR E IN EMPLOYEES WITH E.EMPLOYEE_ID = "00175"
    cont>  MODIFY E USING
    cont>     E.LAST_NAME = "Smathers"
    cont>  END_MODIFY
    cont> END_FOR