Syncing edited attachments

In order to best address my question I shall began by explaining my work flow.

I have EndNote on my laptop and on my desk top.

I am using relative link to store my PDFs.

I sync them through EndNote online.

I edited the PDF’s using Adobe Acrobat.

When I sync my EndNote the changes in my PDFs do not sync.

What can be done to rectify this?

I have looked through the forum and I have not found a solution. Your help is appreciated