There is currently no option to restart your account as it is. The only option you have is to delete your account and create a new account. When you delete your old account, you will also receive a voucher for any STARS you have in your account, so you will be able to use them in your new account.
To redeem a voucher, click the Stars balance in your account, then ''Redeem voucher'' and enter the voucher in the appropriate field:

Only the remainder of the purchased Stars will be included in the voucher you receive after account deletion!
It takes up to 48 hours until an account is fully deleted (the earliest is the next nightly update). This means that you will have to wait until then to register a new account with the same email address. You can, of course, use a different email to sign up and change it later once the other account is fully deleted.


