With Filestar you can easily convert FB2 to ODT. Accessible directly in your right click menu for single or batch FB2 processing. How to convert FB2 to ODT:
1. Download and install the latest version of Filestar. (https://filestar.com)
2. Right click on one or more FB2 file(s) on your desktop and select Convert with Filestar.
Type "convert odt" in the search box.
3. Press Run.