Private Sub Application_ItemSend(ByVal Item As Object, Cancel As Boolean)
Dim outMail As MailItem
If TypeOf Item Is Outlook.MailItem Then
Set outMail = Item
If InStr(1, outMail.subject, "IAH", vbTextCompare) > 0 Then
If MsgBox("Send " & outMail.subject & " ?", vbYesNo) = vbNo Then Cancel = True
End If
End If
End Sub