The MODIFY statement changes the contents of specified data items in a
  database record.

  Format -

   MODIFY [ record-name         ]
          [ { record-item } ... ]

      [          [{| REALM                    |}]         ]
      [RETAINING [{| RECORD                   |}] CURRENCY]
      [          [{| { SET [ set-name ] ... } |}]         ]
      [          [{| { { set-name } ...     } |}]         ]

      [ ON ERROR stment ] [ NOT ON ERROR stment ]

      [ END-MODIFY ]

1 - record-name

  names a database subschema record type.

2 - record-item

  is a group or elementary data item in a subschema record type.
  Record-item can be qualified.

3 - set-name

  names a subschema set type.

4 - stment

  is an imperative statement.