Endpoint Configuration Manager Help Migration to new site Confusion

Hello All,

I hope someone can help me as I have went through the whole process of setting up a new site, SQL, WSUS, everything.  The migration assistant even works and finds the old site.  What I don't get is how my clients will point to the new site instead of the old site. 

I have tried doing it via Discovery which works.  The old site still shows the green checkbox on each client.  I tried uninstalling it manually on one client (which creates a grey x on the client on the old Server), installing the client from the new server does not work.

How do I tell all of our clients to stop looking at the old site and use the new one.   The migration works and moved the collections and devices just fine but I can retire the old server obviously because the clients are still there and green checked.  They are blank in the new site.

Any help would be appreciated since Microsoft doesnt have a phone number for support for this product that I can find.

Old server is 2012R2 with a different site code

New server is a 2019 server with a new site code.

Thanks all!