I had always thought that once you placed a room, you could see it in the next (or any future) phase... but it turns out you can't.
This Revit Tip explains WHY and also shows you how to deal with rooms in renovation projects (or projects with multiple phases).

-------
If your company needs BIM/Revit Assistance.. you can get help without hiring an in-house BIM Manager.
A virtual BIM Manager (me) means you and your team can get immediate help (and ongoing assistance) without dealing with the overhead of hiring someone full time.

Check out my website for more details:
http://www.virtualBIMmanagement.com