If realize you have made a mistake on your registration form after submitting it to your election official, you should contact them to let them know. If you've made a mistake without realizing it, your election official should notify you of this.
Keep in mind that different states will require different things from you in order to rectify this error. If you have any doubt that your correction was accepted, contact your local election official and/or check your registration status online.
To contact your local election official, go to our Election Official Directory and choose your state and voting region. On the following page click the tab marked, “Election Official Contact Details.”
To check your registration status online, go to US Vote's “Am I Registered” service.