@aladdin-sane I agree with Guy, make a new account for the new site. Your rating will fluctuate for a few games, then settle down and average out to reflect your general level. https://www.lexulous.com/v2/ also has some cool new stats and graphs under 'my stats' that allow you to track your progress, monitor your improvement and such, so all that new stuff would be nicely in sync with your new account.

BTW, not sure if you play on website, app, FB etc. I've never seen a 'reset stats' option on the website (where I play). Perhaps that's an option elsewhere, otherwise you'd need to contact admins and ask them to possibly do that for your account. But like I said, a new account/username would be easier. You can still use a regular email and chosen username to sign up, but there are also options to sign in via FB and even Google now.