Under macOS you can rename files when open for read or write; I do it frequently. But for this to work properly, AIUI it relies on that the filesystem notifies apps that this has happened. I imagine that apps have to register for this service and then have to update their internal info about filenames, but I don't know more about it than that. Even MS gets this nearly right in Office. In Office 2016 for macOS, Word could cope with a file being renamed under it and changed the filename it displays in the window title bar; Excel could not.