ASP.NET-Cancel or Delete a membership account from a Database

I have a table in my database called users, have created a Cancel Membership button so that i  registered user would be able to cancel his membership whenever he  wants.
How do i achieve this.My database has a users with fields called FirstName, LastName, EMail,Password. Users normally login with their Email and password details. So please i need a code that will what and NOT only explanations.
?This is the code i used behind my Cancel Membership button but it does not seem to work:
 
Protected Sub btnCancelMem_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnCancelMem.Click 'var to store the email address Dim EMail As String = txtEMail.Text 'var to store the password Dim Password As String = txtPassword.Text 'connect to the database table selecting records matchin ...