Deleting personal data that is processed by UserVoice is a self-service process. You can do this any time you like. You can retrieve a list of UserVoice sites with profiles related to your email address here: Forgot UserVoice Site. Then, follow the steps in this article to delete your profile(s): Delete my Profile/Information.
You will need to login to each UserVoice site using the email address and password that pairs with the profile you want to delete. If you find that you have a password you do not remember, simply click the "Forgot Password" link below the email entry to receive an email that will allow you to reset your password.