How to decommission agent when agent's host no longer available - cannot shutdown agent first

We recently upgraded a database out of place: built a new host with up to date software and migrated the data to it. Before I was tasked with decommissioning the agent on the old host, the host itself was removed. EM knows it cannot communicate with the agent, but will not allow me to decommission it  without first shutting it down. So, I'm stuck. I obviously cannot shut down an agent for a host that no longer exists. How can I get rid of this agent and it's targets? I'm running EM 13.3 OMS is on RH Linux and repository