title: UML modeling tool which can convert a collaboration diagram into a sequence diagram (and back)
body: <p>I was reading about UML Collaboration diagrams and what all of the tutorials mention is that a sophisticated UML modeling tool can easily convert a Collaboration diagram into a sequence diagram. I have looked around at a few and haven't found one that can do this which also runs on a Mac.</p>
  
  <p>If you are aware of such a piece of software, which is still being actively developed, I would be interested.</p>