Charles Proxy Map Remote over HTTP or HTTPS
The Map Remote tool changes the request location, per the configured mappings, so that the response is transparently served from the new location as if that was the original request.
Using this feature for http
resources does't require anything else apart from just configuring your Map Remote entry.
Always make sure you are clearing your cache before you test. Even if Charles is configured properly you might not see the changes unless the browser gets the resource again from the server and not for its local cache.