Logoff after editing a User Role

I'm working on an asp.net-mvc project and would like to force the user to log off after editing a role belonging to the user, using asp.net-identity

public async Task<ActionResult> Edit(string id)
    {
        if (id == null)
        {
            return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
        }
        var role = await RoleManager.FindByIdAsync(id);
        if (role == null)
        {
            return HttpNotFound();
        }
        RoleViewModel roleModel = new RoleViewModel { Id = role.Id, Name = role.Name };
        return View(roleModel);
    }

    //
    // POST: /Roles/Edit/5
    [HttpPost]

    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Edit([Bind(Include = "Name,Id")] RoleViewModel roleModel)
    {
        if (ModelState.IsValid)
        {
            var role = await RoleManager.FindByIdAsync(roleModel.Id);
            role.Name = roleModel.Name;
            await RoleManager.UpdateAsync(role);
            return RedirectToAction("Index");
        }
        var autheticationUser = HttpContext.Current.GetOwinContext().Authentication;
        autheticationUser.SignOut();
        return View();
    }