title: Update role with aspnet membership provider
body: <p>I have a RadioButtonList "chklRoles" which has 4 buttons. I want to update database aspnet_UserInRoles if I select a role. But it seems that the Aspnet Membership Provider doesn't have an update method. How can I do it?</p>
  
  <pre><code> protected void chklRoles_SelectedIndexChanged(object sender, EventArgs e)
      {
          foreach (string role in Roles.GetRolesForUser(userName))
          {
              if (chklRoles.Items.FindByText(role).Selected == true)
              {  
                  // update role;
                 // Roles.DeleteRole("origin_role");
                 //  Roles.AddUserToRole(userName, role);
              }
          }
      }
  </code></pre>
  
  <p>Edit: I think that to delete it and add it with a new role maybe an option. But please give me an advice.
  update: each user only can have one role. What I want is how to switch roles by clicking the radio button. Update meants a new role will replace the older role.</p>