I do not know if this will work, but this was given to me by Tech:

Go to your account page, towards the bottom of the page is your Order Summary. Click on the text of the appropriate pre-release order and that will take you to the Final down load page. Make sure you un-install the pre-release before you install. Also, save any objects or scenes that you want to keep and add to the final version.   Then download the new Patch and install.

This may or may not work, but is worth a try.

jankeen.com