I was also looking for same and reached a easy solution u can try this out
Follow these simple steps:-
1.Drag and drop it xfa format PDF into chrome ,it will open in chrome browser.
2.You will find three options at right corner
3.click on print
4.Change destination "save as PDF" and save.
Saved PDF is flat PDF(Acroform) and can be edited easily
[details removed by ussnorway]
With Adobe Acrobat you can print to "Adobe PDF".
Tried that on the MacOS Reader application. It just whines that I should do a "File - Copy". Which *****DOESN'T***** remove the XFA functions. Which means the file STILL can't be opened in Ocular, Evince, or the MacOS previewer.
Don't need it to be editable once it's filled out. I need it viewable.
A PDF without form fields – which is what you have when you “print to PDF” is NOT an AcroForm!! An AcroForm uses live/interactive form fields as defined in ISO 32000-1:2008.
Second, this process is EXTREMELY LOSSY! Not only to the form itself – losing all business rules, etc – but to the PDF, since Chrome’s PDF creation engine doesn’t support all the possible features of a PDF (or XFA-based PDF).