Transfers data from internal storage and writes the data
  (translated if formatted; untranslated if unformatted) to the
  current record in the following types of files:  an indexed,
  sequential (only if the current record and new record are the same
  length), or relative file.

  The current record is the last record accessed by a preceding,
  successful direct access, indexed, or sequential READ statement.

     Formatted REWRITE statement format:

      REWRITE ([UNIT=]u,[FMT=]f[,ERR=s][,IOSTAT=ios])[iolist]

     Translates the data from binary to character format as
     specified by FMT.

     Unformatted REWRITE statement format:

      REWRITE ([UNIT=]u[,ERR=s][,IOSTAT=ios])[iolist]

     Does not translate the binary data.

     Arguments:

     u       Is an integer variable or constant specifying the
             logical unit number of the file, optionally
             prefaced by UNIT=.  UNIT= is required if unit is
             not the first I/O specifier.

     f       Is a format specifier.

     s       Is the label of a statement to which control is
             transferred if an error condition occurs, prefaced
             by ERR=.

     ios     Is an integer variable to which the completion
             status of the I/O operation is returned, prefaced
             by IOSTAT=.

     iolist  Are the names of the variables from which the data
             is transferred, listed in the order of transfer.

  Formatted REWRITE Statement Behavior and Errors:

  The formatted REWRITE statement performs the following operations:

   o  It retrieves binary values from internal storage.

   o  It translates those values to character form as specified by
      FORMAT.

   o  It writes the translated data to a current (existing) record in
      a file OPENed with ORGANIZATION='INDEXED', 'RELATIVE', or
      'SEQUENTIAL' (For SEQUENTIAL organization, the new record must
      be the same length as the existing record.)

      The current record is the last record accessed by a preceding,
      successful indexed, direct access, or sequential READ
      statement.

  Errors occur under the following conditions:

   o  If you attempt to rewrite more than one record in a single
      REWRITE statement operation

   o  If a record is too long (Note that unused space in a rewritten,
      fixed-length record is filled with spaces.)

   o  If the primary key value is changed

  In the following example, the REWRITE statement updates the current
  record contained in the relative organization file connected to
  logical unit 3 with the values represented by NAME, AGE, and BIRTH.

           REWRITE (3,10,ERR=99) NAME, AGE, BIRTH
     10    FORMAT (A16,I2,A8)

  Unformatted REWRITE Statement Behavior and Errors:

  The formatted REWRITE statement performs the following operations:

   o  It retrieves binary values from internal storage.

   o  It writes the untranslated data to a current (existing)
      existing record in a file OPENed with ORGANIZATION='INDEXED',
      'RELATIVE', or 'SEQUENTIAL' (For SEQUENTIAL organization, the
      new record must be the same length as the existing record.)

      The current record is the last record accessed by a preceding,
      successful indexed, direct access, or sequential READ
      statement.

  Errors occur under the following conditions:

   o  If you attempt to rewrite more than one record in a single
      REWRITE statement operation

   o  If a record is too long (Note that unused space in a rewritten,
      fixed-length record is filled with zeros.)

   o  If the primary key value is changed