Document.Kind (Word)

Returns or sets the format type that Microsoft Word uses when automatically formatting the specified document. Possible return values are wdDocumentEmail - Email format, wdDocumentLetter - Letter format, wdDocumentNotSpecified - No format specified.

response = MsgBox("Is this document an email message?", vbYesNo) 
If response = vbYes Then 
 ActiveDocument.Kind = wdDocumentEmail 
 ActiveDocument.Content.AutoFormat 
End If