Although some sites claim that it is possible to convert PDF documents (probably with Visio diagrams) back to Visio's VSD format, it is highly unlikely. What they offer is export to JPG/PNG which you can import to Visio as object.
At best, you could create a picture of the diagram and use it, but you won't get the Visio data back from PDF.
Updated: March 8, 2017
This conversion entry was verified by us and conversion was flagged as wrong or not possible.
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