Some file archive programs like FreeArc support both .ark and .arc archives and can re-pack one to another. Hence, this is the obvious choice for ark to arc conversion. Whenever this is actually useful or done for specific reasons could not be reliably verified.
Convert ARC File Archiver CPM/Port archive to FreeArc compressed archive.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert ark to arc on Windows
A multi-platform archiving application
Convert from ark 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.