The EdgeRules feature is available only on Enterprise plans.
The following example shows how to handle the request Host header and alter it based on the value in the local NginX variable $scheme. The idea is to use domain-one.com in the Host header for requests coming in via the HTTP and domain-two for https. 
Nginx configuration block
location / {
if ($scheme = http) {
set $request_host "domain-one.com";
}
if ($scheme = https) {
set $request_host "domain-two.com";
}
proxy_set_header Host $request_host;
If Origin Shield is enabled in your zone, you may see the following line: proxy_set_header Host $request_host. Don’t be alarmed though. This directive is ignored on the edge server and applied to the Origin Shield configuration instead.
If you have any questions or experience any issues, please reach out to the Support Team, live chat and ticket support are available 24/7.