As mentioned in documentation (http://help.abbyy.com/en-us/flexicapture/12/formdesigner/export_pdf), After exporting an image to the PDF format, you will be able to edit it in other form editing programs, such as Adobe Acrobat Professional.
The trial version of Adobe Acrobat Pro DC (not Reader) allows opening PDF form. It is fully editable and could be saved. Furthermore, it allows saving it as a Reader Extended PDF. After saving the document in this format it can be edited in Adobe Acrobat Reader.
Some important notes:
- From Adobe Acrobat Reader the form cannot be saved after editing. It can be edited and printed, but saved it could be only with Adobe Acrobat Pro.
- Like some kind of workaround "Printing as PDF" can be suggested.
After editing a form in Adobe Reader you may try to print it using Microsoft Print to PDF.
The additional information about editing forms in Adobe may be found here: