EF Reinsert

protected void Page_Load(object sender, EventArgs e)
{
    if (IsPostBack == false)
    {
        long id = Int64.Parse(Request.QueryString["Id"]);

        using (var context = new LabContext())
        {
            var request = context.REQUEST.Where(r => r.ID == id).SingleOrDefault<REQUEST>();

            var query1 = context.PATIENTTYPE;
            this.PatientType.DataSource = query1.ToList();
            this.PatientType.DataValueField = "ID";
            this.PatientType.DataTextField = "DESCRIPTION";
            this.PatientType.DataBind();

            if (request != null)
            {
                PatientType.SelectedValue = request.PATIENTTYPE.ToString();
            }
        }
    }
}

protected void SaveButton_Click(object sender, EventArgs e)
{
    using (var context = new LabContext())
    {
        long id = Int64.Parse(Request.QueryString["Id"]);
        long header = Int64.Parse(Request.QueryString["Header"]);

        var request = context.REQUEST.Where(r => r.ID == id).SingleOrDefault<REQUEST>();
        if (request == null)
                {
                    request = new REQUEST();
                    request.HEADER = header;
                    context.REQUEST.Add(request);
                }

        request.PATIENTTYPE = Int64.Parse(this.PatientType.SelectedValue);
        context.SaveChanges();
    }
}