Moving Data from One Tag to Another

I often want to copy data from one tag to another (E.g., movement info to title or conductor to artist, or deal with imported data that lists the composer as the artist). Is there a way to do this in MP3Tag? What I'd really like is if the Replace and Regex Replace actions allowed me to specify a target tag independently of the source tag.

you did not even try to look at the FAQ, didn't you? Well then, have a look at
/t/967/1

and then try to explain how you think it should be done to guess which field/tag you prefer to be copied into a specific field/tag. If you can explain that then there might be a way.
The DWIM method ("DO WHAT I MEAN") is still being under research.