cluster.peer update in alertmanager -Prometheus operator

[Radha R4]

I am getting below error ,

    State:       Waiting
      Reason:    CrashLoopBackOff
    Last State:  Terminated
      Reason:    Error
      Message:   level=info ts=2020-05-08T00:12:12.177Z caller=main.go:231 msg="Starting Alertmanager" version="(version=0.20.0, branch=HEAD, revision=f74be0400a6243d10bb53812d6fa408ad71ff32d)"
level=info ts=2020-05-08T00:12:12.177Z caller=main.go:232 build_context="(go=go1.13.5, user=root@00c3106655f8, date=20191211-14:13:14)"
level=warn ts=2020-05-08T00:12:12.273Z caller=cluster.go:228 component=cluster msg="failed to join cluster" err="1 error occurred:\n\t* Failed to resolve alertmanager-prometheus-operator-alertmanager-0.alertmanager-operated.kube-system.svc:9094: lookup alertmanager-prometheus-operator-alertmanager-0.alertmanager-operated.kube-system.svc on 172.20.0.10:53: no such host\n\n"
level=info ts=2020-05-08T00:12:12.273Z caller=cluster.go:230 component=cluster msg="will retry joining cluster every 10s"
level=warn ts=2020-05-08T00:12:12.273Z caller=main.go:322 msg="unable to join gossip mesh" err="1 error occurred:\n\t* Failed to resolve alertmanager-prometheus-operator-alertmanager-0.alertmanager-operated.kube-system.svc:9094: lookup alertmanager-prometheus-operator-alertmanager-0.alertmanager-operated.kube-system.svc on 172.20.0.10:53: no such host\n\n"

I want to know how to update the alert manager service name in this below config of prometheus operator,

   Args:
      --config.file=/etc/alertmanager/config/alertmanager.yaml
      --cluster.listen-address=[$(POD_IP)]:9094
      --storage.path=/alertmanager
      --data.retention=120h
      --web.listen-address=:9093
      --web.external-url=http://prometheus-operator-alertmanager.kube-system:9093
      --web.route-prefix=/
      --cluster.peer=alertmanager-prometheus-operator-alertmanager-0.alertmanager-operated.kube-system.svc:9094

Here is my service:

prometheus-operator-alertmanager               ClusterIP   172.20.124.167   <none>        9093/TCP                       10m