Most Helpful Guy
I don't think that's possible without the original HD source if there even is one.0
Most Helpful Girl
You can't. It's like expecting a donkey to become a horse.
The best way to explain it is with image sizes. If you have an image that is 10 dpi and you blow it up to 1,000 dpi, because the original image didn't have the pixel quality and resolution, your image will look blurry. However if you did it the other way around it's fine. You have that detail "saved" within the picture, it doesn't have to magic it from anywhere.
The same goes for video. If it's shot in had it can be made smaller, but not the other way around. The information isn't there.0