Unfortunately at this time it is not possible to change the location of the button. You can disable it completely and when you want to download a video, you can manually open Downloader and enter the URL. Here are steps to disable the Downloader button.
1. Open RealDownloader.
2. Click the RealDownloader logo from the top left corner and click Preferences.
3. Uncheck "Turn on Download This Video in Chrome, Edge and Firefox browsers:"
4. Click OK
To manually download videos, open RealDownloader and click "Download a video from a web link" and paste the URL.