Reverting back to Community Edition?

I have installed the trial version of the Standard Edition to try but I have already decided that as I am not using it for a commercial project I want to now revert back to the Community Edition. I have tried uninstalling and reinstalling but it reinstalls back to the trial of the Standard Edition.

I still have 20 days remaining on the trial but I would like to revert back to the Community Edition immediately. Can this be done?