I am using Evernote windows based client and have purchase the PREMIUM version. I create a notebook, then invited a colleague user to share it. As our emails come through the same client, I accidentally accepted the invitation when logged in as myself rather than the colleague. When the colleague tries to accept the invitation through the email he receives this error message: " Shared notebook assigned to another account. This shared notebook is assigned to another user. Contact the notebook owner to obtain an invitation." I see no way to unshare the notebook, so please can you help?