public ActionResult StopImpersonation()
 {
     using (var repository = RepositoryFactory.GetInstance())
     {
         var userManager = new MyMentorUserManager(repository, Session, HttpContext);
         userManager.StopImpersonation();
         return RedirectToAction("index", "MyAccount");
     }
 }
        private async Task<MyAccountViewModel> GetMyAccountVm(MyAccountRequest request, IMyMentorRepository repository)
        {                        
            var model = new MyAccountViewModel {MyAccountRequest = request};
            var isAdmin = Session.GetLoggedInUserRoleName() == RoleNames.ADMINISTRATORS || !string.IsNullOrEmpty(Session.GetImpersonatingUserName());
            var currentUser = Session.GetLoggedInUser();
            var isFirstTimeInPage = Request.QueryString.AllKeys.All(x => x.ToLower() != "uid" && x.ToLower() != "pn");
            var userManager = new MyMentorUserManager(repository, Session, HttpContext);

            if (isAdmin && currentUser.Username != request.Uid && !isFirstTimeInPage)
            {
                if (!string.IsNullOrEmpty(request.Uid))
                {
                    var user = await repository.FindUserByUserName(request.Uid);
                    if (user != null)
                    {
                        model.ErrorMessage = string.Empty;
                        model.UserName = user.UserName;
                        model.UserDispalyName =string.Concat(user.GetLocalizedField("FirstName") ," ", user.GetLocalizedField("LastName"));
                        model.MyAccountRequest.Uid = user.ObjectId;

                        if (Session.GetImpersonatingUserName() != model.UserName)
                            await userManager.ImpersonateUser(user.UserName);
                        else
                            userManager.StopImpersonation();
                    }
                    else
                    {
                        model.ErrorMessage = MyMentorResources.userNameDoesNotExist;
                    }
                }
                else
                {
                    userManager.StopImpersonation();
                }
            }
            else
            {
                model.UserName = currentUser.Username;
                model.UserDispalyName = currentUser.GetFullName(Language.CurrentLanguageCode);
                model.MyAccountRequest.Uid = currentUser.ObjectId;
            }

            return model;
        }