Follow these steps:
1. Exit from TuskTools Calendar.
2. Right-click on the TuskTools Sync icon in your Windows system tray.
3. From the context menu, select "Log Off".
4. A login dialog should appear; enter the information for your new Evernote account. (It's recommended that you check the "Remember me on this computer" checkbox.)
5. You'll then see a dialog informing you that TuskTools is performing an initial sync with your new Evernote account. When this sync is completed, you'll see a notification balloon above your Windows system tray. At that point, you can launch TuskTools Calendar with your new data.