11-20-2018 11:29 AM - edited 11-20-2018 11:43 AM
Copy the record in library list view and paste, now open the duplicate and modify. (oops, sorry, the first time I read this request I noted ref type, but just now, I assumed duplicate a record not the ref type, my bad).
So you could try creating your new ref type, then export the file. Using a text editor to copy and paste a copy of the one you want to duplicate, replacing most of your original ref type details. I didn't try it, but searching for "name" finds the ref types, and you could find the one you wanted, copy and paste and to the "name" details of your empty renamed unused ref type? Then reimport and see what happens? Back up libraries, and styles I guess to be safe, as you might need to repair or reinstall Endnote if it breaks!
You could also purchase an xml editor I guess.
Otherwise, take a screen shot of the current settings for the one you want to copy and then manually enter them into one of the unused templates. I know. Not automated.