Monitoring non-Persistent Hosts

I am Sorry if this might be the wrong Category for this topic but i have a question regarding monitoring not persistent hosts.
We are using Icinga for windows to monitor some of our Servers and it works great.
The only problem arises when trying to Monitor non-Persistent Hosts.
We are using the Citrix Machine Creation Services to generate a number of Remote Session Hosts using one Master Image. After a reboot the Machines are generated from the Image anew and lose the Icinga Agent including the Configuration. Installing and setting up the Agent on the MCS Image is sadly not an option since the same Image is used for multiple session hosts.
Now it would be no problem to create a Script that automatically Installs the Agent as soon as the Machine boots up, however the Agent cannot be Registered with the Icinga Director since there is allready has a saved Host API key for a machine with the same name.
Once the Key gets dropped, the script runs trough with no problems.
so here`s my question: i know the self service API is working as intended since it rejects the request if the machine is allready registered and has a key. but is there a way to automate the process of droping the key in the Director (for example through a script)?
Are there perhaps other methods more suitable for this setting that i am not aware of?
has someone more experince with monitoring non-Persistent Machines?

you can use the icinga director api to drop the api key as a part of you rebuilding process, or a a part of your re-registering script

→ update the host and remove the apikey attribute

I am sorry but im not entirely sure what you mean.
I know that i can manually drop the key for a host in the director if that is what you mean.
The problem is that the hosts reboot each night and one has to manually drop this key before they are able to register themselves again via the script.
i have found a way to drop the key but only locally on the host itself which doesnt change much as the key is still present in the director so it refuses the new registration. Is there a way to remove the key from the director without having to do it manually?

[REST API - Icinga Director]

GET director/host?name=pe2015.example.com

{
  "address": "127.0.0.3",
  "api_key": "xxxxxxx",
  "check_command": null,
  "check_interval": null,
  "display_name": "pe2015 (example.com)",
  "enable_active_checks": null,
  "flapping_threshold": null,
  "groups": [ ],
  "imports": [
    "generic-host"
  ],
  "retry_interval": null,
  "vars": {
    "facts": {
      "aio_agent_build": "1.2.5",
      "aio_agent_version": "1.2.5",
      "architecture": "amd64",
      "augeas": {
        "version": "1.4.0"
      },
   ...
}

remove api key from json

PUT director/host?name=pe2015.example.com
mit den daten aus dem json ohne api_key