Is there a concept of Re-deploying? Specifically, if you deploy a process definition and then want to change that process, do you have to use createDeployment().deploy()?

I came across this post: http://community.jboss.org/message/521647#521647 which had responses suggesting that re-deployment is really just doing a new deployment. However, I notice that causes multiple deployment rows to appear in the database. Also, how would versions of process definitions ever come into play?