How forward response headers in pod application

Hello everyone.
Sorry for my bad english, I’m from Russia.
I have a problem setting up istio in a kubernetes cluster.
The cluster has a pod that makes a request to a resource outside the cluster, and receives a response. There is a header in the response which has the nginx version, but in the response I get “server: envoy” in the header.
How can I make istio not change the response header?
Thank you.