If you have an empire lot from version 1.6.4 (or older), you should have just received an email. If not, please go to this page, read it well and fill out the form, thanks!
IMPORTANT UPDATE: If you want to reset your lot, but are not ready, please just chose “keep”. You can chose to reset it anytime in the future. From the 16th of December on, once you select “reset”, it will be reset at the next restart of the server. Only moving lots will be processed by ranks.
Also, you can see the progress of lot resets on this page.