With the StuffIt program that is popular on Apple Mac platform you can easily convert SITX archivers to their WinZIP equivalents - ZIP archives.
Convert StuffIt archive to WinZIP Compressed ZIP archive.
We have found 3 software records in our database eligible for .sitx to .zip file format conversion.
Apple macOS / Mac OS X software - convert sitx to zip on OS X
A compression tool for Apple Mac OS X
Convert from sitx 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 sitx to zip. 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.
Mac version of the popular utility
A backup and archive utility