In case of you renamed a Failover Cluster in Failover Cluster Manager which is connected to a SCVMM 2012 R2 you will see that the renaming will not be reflected in SCVMM 2012 R2.
Under these circumstances you can basically rename the Failover Cluster over the VirtualManagerDB > dbo.tbl_ADHC_HostCluster > Name Column as follows.
1. Connect to the VirtualManagerDB via SSMS. 2. Expand tables and navigate to dbo.tbl_ADHC_HostCluster. 3. And rename the Failover Cluster under the Name column.
1. Go to dbo.tbl_ADHC_HostCluster.
2. Find your Cluster Name under the Name column, rename and save it.
Good luck !