I have a rather complicated XSLT mapping between two XSD files for doing an export of our schema to another organization. We also need to import data from that organization back into our system. Is there any way to just swap the flow for the import XSLT, or do I need to redo a completely new mapping?
Processes written in Turing-complete languages are not, in general, guaranteed reversible; XSLT is no exception. It's an interesting problem, and there may be some literature on it, but I doubt that there are any tools intended for practical use.
If your mapping is in fact reversible, and your XSLT is reasonably clear, your second stylesheet will be somewhat easier to write than the first one. That's something, at least.