public ActionResult EventSelection(int eventWaveId, int registrationId)
        {
            var eventObj = _registrationService.GetRegistrationById(registrationId);
            var result   = _registrationService.ChangeEvent(registrationId, eventWaveId, null, null);

            if (!result.Success)
            {
                Utilities.AddModelStateErrors(this.ModelState, result.GetServiceErrors());
            }
            return(RedirectToAction("ViewUser", "User", new { id = eventObj.UserId }));
        }