“The READ operation reads the record, currently pointed to, from a full procedural file (identified by an F in position 18 of the file description specifications).
The name operand is required and must be the name of a file or record format. A record format name is allowed only with an externally described file (E in position
22 of the file description specifications). It may be the case that a READ-by-format-name operation will receive a different format from the one you specified in the name operand. If so, your READ operation ends in error.
If the data-structure operand is specified, the record is read directly into the data structure. If name refers to a program-described file (identified by an F in position
22 of the file description specification), the data structure can be any data structure of the same length as the file?s declared record length. If name refers to an
externally-described file or a record format from an externally described file, the data structure must be a data structure defined with EXTNAME(…:*INPUT) or
LIKEREC(…:*INPUT).”

You don’t have to use a data structure. You can if you want to. If you do, then specify the data structure accordidng to the quotation.

FRESULTS IF A E DISK RENAME(RESULTS:RESULTR)

DOUTDS DS LIKEREC(RESULTS:*OUTPUT)
DINDS DS LIKEREC(RESULTS)

C READ EPPATEMPW1 INDS
C
C* Make your changes to INDS fields here
C
C Eval OUTDS = INDS
C WRITE RESULTR OUTDS

Hope this works for you.

When you use an externally-described file you don’t need to define a data structure. You move the values to each of the fields in the externally-described file and then you use the WRITE operation code, with the Result Field empty.