This is a technical answer - use at own risk!!!
Preview will no longer allow you to save documents back into documents which live in the user library folder.
Evernote stores our documents in /Users/myuseraccount/Library/Application Support/com.evernote.Evernote/accounts/www.evernote.com - most likely a good design!
I know my way around the terminal - so this is what you can do:
cd /Users/myuseraccount/Library/Application Support/com.evernote.Evernote/accounts/
mv www.evernote.com ~/Documents
ln -s ~/Documents/www.evernote.com
First line moves the terminal into the evernote database folder. Second line moves the database folder to the users document folder. Third line makes a link from the original database folder to the documents folder.
The result is that Evernote continues to work, and Preview now thinks the files are in the Documents folder (which they are), and allow us to edit them.
This is not really the right way to do this - But it will work until Apple and Evernote sort out their stuff.