If you upgrade the operational database and the data warehouse from any computer that is not the Operations Manager 2007 ...

If you upgrade the operational database and the data warehouse from any computer that is not the Operations Manager 2007 R2 root management server (RMS), the RMS is removed from the management group. We recommend this option when you have an RMS that is clustered or that does not meet the minimum supported configuration for an System Center 2012 - Operations Manager management server.