Special utilities for managing of Kindle ebooks, like KindleGen should be able to convert various digital publications to formats usable on Kindle readers. May not always work with DRM-protected books, but usually should be working without problem.
Convert Amazon Kindle Format 8 to Mobipocket eBook format.
We found one software available in the database for this conversion.
Microsoft Windows software - convert kf8 to mobi on Windows
A command line tool for converting ebook formats
Convert from kf8 file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.