I changed my cluster and data center compatibility from 3.5 to 3.6 with a 3.5 host.  D'oh!

Engine: 3.6 on FC22

Host: 3.5 on FC22 (local storage)

- Can I change the data center and cluster back to 3.5?  How?

- I tried to upgrade host to 3.6 in the GUI.  Maintenance->Reinstall did not work, and Upgrade option is greyed out.  Is there a way to upgrade host to 3.6?