Does EF upsert have to be done manually?

I want to upsert reference members of an existing entity.

Do I have to write specific code for the upsert?

meaning: I have to check if I'm handling an existing reference member or a new one.

Is there any other simple way to do so?

What happens when you do only Save ?

  public void SaveCofiguration(MamConfiguration_V1Ui itemUi)
        {
            var itemEf = mMamConfiguration_V1UiToEfConvertor.ConvertToNewEf(itemUi);

            using (var maMDBEntities = new MaMDBEntities())
            {
                IDal<MamConfiguration_V1> mamConfigurationDal = mDalFactory.GetDal<MamConfiguration_V1>(maMDBEntities);

                mamConfigurationDal.Save(itemEf);
            }
        }

         public MamConfiguration_V1 GetById(object id)
        {           
                id.ThrowIfNull("id");

                int configurationId = Convert.ToInt32(id);

                var result =
                    mMaMDBEntities.MamConfiguration_V1.SingleOrDefault(item => item.ConfigurationId == configurationId);

                return result;

        }

       public MamConfiguration_V1 Save(MamConfiguration_V1 item)
        {

                item.ThrowIfNull("item");

                var itemFromDB = GetById(item.ConfigurationId);

                if (itemFromDB != null)
                {
                    UpdateEfItem(itemFromDB, item);

                   // if (mMaMDBEntities.ObjectStateManager.GetObjectStateEntry(itemFromDB).State == EntityState.Detached)
//                    {
  //                      mMaMDBEntities.MamConfiguration_V1.AddObject(itemFromDB);
    //                }

                    // Attached object tracks modifications automatically
                    mMaMDBEntities.SaveChanges();

                    return item;
                }





       private void UpdateEfItem(MamConfiguration_V1 itemFromDb, MamConfiguration_V1 itemFromUi)
            {