.. The test server is not connected to our production network. Is there a way to change the groupwise password with out connecting to or installing a replica of our production eDirectory on the test server?.
You should read this TID:
Recover deleted mail for legal action
Following this method you do not even need a post office agent.
I'm afraid that method to reset/clear the user password in steps 4 to 6
of the alst paragraph don't work consistently. On some accounts it will
work, on others not. You will end up having to run a real MTA and POA
anyways to get the password changed.