YouTube "move" playlist not "copy"

I have two separate Google account's, Old& New). Old has multiple YouTube playlists that I'd like to transfer to New.

I am able to add a YouTube playlist from Old to New, but afterwards, any changes I make to it in Old, such as renaming, or deleting it, also affect the same playlist in New.

How can I make the newly added playlist in New independent from the original playlist in Old?