You are able to edit any of your renders you have made in the new platform simply by going to your 'my video' section, however, any made prior to the new version will not be able to be edited.
Under the video, there is an edit button. You can then change the colours, any images or text and re-render the video.
Both videos will be accessible in your video section but you can always delete any you don't wish to keep.
Please note: All videos will be removed from your My Videos page after 30 days. If you would like to keep a video longer, simply edit it and render it again. This will allow you to keep the new version for a further 30 days.