Shawn,
The Agents won't automatically reconnect. When they connected to your original LEM, they would have exchanged certificates for encrypting the log traffic. These certificates are not going to be valid for the new LEM because they're generated at the time of deployment, so the Agents won't be able to connect (LEM will reject the connections because the certs are wrong) until you remove the old certs and set the Agents back to a "first run" state. Support has a tool to bulk-reset Agents in cases like these, so I would check with them for that.