Updating identity table aspnetuser in mvc web application

Question

I am using asp.net identity for signup and signin for email confirmation i am using my own code but on email confirmation i want to update the records in aspnetuser table like emailconfirmed field to true , but it is not updating

and db.savechanges()>0 always false

check the below code.

public JsonResult RegisterConfirm(string regId)
{
OurHealthisWealthEntities db = new OurHealthisWealthEntities();
var userList = UserManager.Users.Where(x=>x.Id==regId).FirstOrDefault();
userList.EmailConfirmed = true;
userList.PhoneNumber = "123123123123";
//db.Entry(userList).State = EntityState.Modified;
if (db.SaveChanges()>0)
{
var msg = "Your Email Is Verified!";
return Json(msg, JsonRequestBehavior.AllowGet);
}
else
{
var msg = "your email is not verified!";
return Json(msg, JsonRequestBehavior.AllowGet);
}
}

Even committed line when uncomment it still not updating the record