Converting a field name

I want to change some field names to other field names. I have created an action group.

As an example i want to convert DISCOGS_CATALOG to LABELNO but still keep the field data. Perhaps I'm not looking closely enough, but I'm not seeing this option in actions.

Thanks in advance...

you've to make a new action:

Format Value
Field: LABELNO
Format String: %DISCOGS_CATALOG%

If you get the DISCOGS_CATALOG from a websource script, you can also edit this script directly. Open it with notedpad, search the line
outputto "DISCOGS_CATALOG"
and change it to
outputto "LABELNO"

I would recommend to use CATALOG # instead of LABELNO, it's more standard.