Various compressed archives can be simply converted between each other when you extract the original archive and compress it in the new archive type you want. In case of split, multi-volume archives you need to gather all the original pieces first.
Convert Unix CPIO archive file to Compressed file from a multi-volume archive (part 8).
We found 2 software records in the database related to .cpio to .008 file format conversion.
Microsoft Windows software - convert cpio to 008 on Windows
Popular open source file archiver with a high compression ratio
Convert from cpio file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned cpio to 008. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
A free open source archive utility