Today I had the task of migrating a number of systems over to the SCOM 2012 server with the existing server being offline. Running the normal discovery fails to redirect the nodes over to the system because of a pair of registry entries still pointing to the old system. The below batch script can be run one at a time or via some automation method (Config Manager in my case) to mass-migrate nodes over to the new system.
@REG ADD "HKLM\SOFTWARE\Microsoft\Microsoft Operations Manager\3.0\Agent Management Groups\LiquidObject\Parent Health Services\0" /v "AuthenticationName" /d "SCOM-1.liquidobject.com" /f @REG ADD "HKLM\SOFTWARE\Microsoft\Microsoft Operations Manager\3.0\Agent Management Groups\LiquidObject\Parent Health Services\0" /v "NetworkName" /d "SCOM-1.liquidobject.com" /f @NET STOP HEALTHSERVICE @NET START HEALTHSERVICE