Буду использовать для реализации задачи по замене значения targetUri в deploymentclient.conf splunk agent forwarder.

(Get-Content -path "C:\Program Files\SplunkUniversalForwarder\etc\system\local\deploymentclient.conf" -Raw) -replace 'targetUri = server1:8089','targetUri = server2:8089' | Set-Content -Path "C:\Program Files\SplunkUniversalForwarder\etc\system\local\deploymentclient.conf"

Ну и restart splunk agent

."C:\Program Files\SplunkUniversalForwarder\bin\splunk.exe" restart