This is a useful tool if you have embeded your video on a website and want to change the content without editing the code.
To do this simply select this button found in the video page and you will be taken through the upload process
↑ Image above is a screenshot
Once the video has been uploaded the video content will be replaced automatically. This means the embed code has not changed but the video has so in all instances where this embed code is on the internet the new content has replaced to old.
If the replacement video was shot in a different size or aspect ratio then it will be encoded to fit the size of the original player selected