Deployment of a Role Questions

I have gone through documentation for both Nware and the Nion hardware, but I cant seem to find a definitive answer.   This actually may be a very silly question.  I am just now finally getting the chance to modify roles and deploy them, and I ran into a slight problem.   When attempting to deploy a role to one of my NION N3's.. it gets stuck on the error message, "Stopping current Role".. and just hangs.  I end up  having to power down the box from the front LED panel and then redeploy the role to the box to get it back up. 

Question is: Do we hae to stop the current role on the box before attemptin to deploy a new role to it?  I am assuming that is the case, but I wanted to verify it here if possible.   Also, is there a checklist anyone can either suggest or provide of things to just double check before deploying a new role to a NION box? 

Thanks in advance.