Password Change control in ASP.NET

hello guys i have a login control which is working fine. but i need to add Change password Control.. Can some one pls suggest how to approch code behind script?
my C# code for Login is as follows:
 protected void Login1_Authenticate1(object sender, AuthenticateEventArgs e)    {        try        {            string uname = Login1.UserName.Trim(); //Get the username from the control            string password = Login1.Password.Trim(); //get the Password from the control            bool flag = AuthenticateUser(uname, password);            if (flag == true)            {                e.Authenticated = true;                Login1.DestinationPageUrl = "Menu.aspx";        ...