There doesn't seem to exist any direct way how IWA files could be converted to anything else. These *.iwa files are found inside compressed documents from iWorks (*.pages, *.numbers etc.) and replaced the previously used XMLs that were utilized for the document structure.
If you want to convert your document, you will need to convert it as whole, not just a part from inside.
It may be possible to somehow decode the IWA files (they feature Snappy compression) and rebuild some kind of "old" version of iWorks documents, but that seems like highly unreliably and complicated way.
This conversion entry was verified by us and conversion was flagged as wrong or not possible.
Usually this happens when the conversion would try to convert different types of data between each other, such as audio to image, or it is not possible because incompatibility between programs, caused by closed file formats, very limited support etc.
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