How to avoid fiddler discard my header: host?

Question

This is my C# code:

var url = "http://10.2.0.2/api";
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.Referer = url;
request.Host = "wwww.abc.com";
request.Accept = "*/*";
HttpWebResponse response = (HttpWebResponse)request.GetResponse();

while I run the code, and open fiddler to capture request, I found fiddler discard header: Host,
so my IIS returned an error!

How did I avoid it? Why fiddler discards Host but keep other headers?

Question: another

was header be changed, my question was header be discard.

I found my solution, open FiddlerScript, and add these script:

     static function OnBeforeRequest(oSession: Session) {
            var sOverride = oSession["X-Original-Host"];
            if (!String.IsNullOrEmpty(sOverride)) 
            {
                oSession.oRequest.headers["Host"] = sOverride;
            }