About two weeks ago, I'd discovered that one of the projects I'd created months ago was tagged against the wrong year. I visited Australia twice, once in 1999 and again in 2000. I mistakenly imported photos taken in 1999 into an "Australia 2000" project. My project & master naming scheme is simplistic - - it does include the year in the names. And my hierarchy for my referenced masters mimics my Aperture folder and project layout. An example referenced master is "Australia 2000/Australia 2000 001.NEF". For my organizational scheme, fixing this up meant dealing with:

the project name
the version names
the master file names
the master file locations

I knew the project name and master file locations would be easy. But I wasn't certain how I'd deal with the version and master file names. Figuring I was in for a time consuming bout with the system to correct my mistake, I kept putting this off.

This past weekend I finally sat down to correct this. Man... I was pleasantly surprised how easy this was with Aperture. I think the whole process took me 10 minutes, with 7 of those taken up convincing myself I'd actually done what I wanted.

Three steps. That's it.

Check "Apply to Master Files" to rename the masters

The project name: This is the easy one. Rename the project. In my case, from "Australia 2000" to "Australia 1999". Then drag and drop it to an "1999" folder in my "Travel" hierarchy.

Checkpoint: Referenced masters are still reside in an "Australia 2000/Australia 2000 ###.NEF" hierarchy.
The version & master file names: Make sure all my stacks are open and select all of the versions. Then, Metadata --> Batch Change. For me, the "Custom Name With Counter" fit the bill, but with all the various version naming schemes available here, this should apply to just about anyone. Check "Apply to Master Files" and click OK (screenshot below). This worked beautifully.

Checkpoint: The version names are correct. Referenced masters now look like "Australia 2000/Australia 1999 ###.NEF". Getting closer.
The master file locations: Lastly, select the project and do File -> Relocate Masters for Project. In the dialog, I created an appropriate "Australia 1999" folder and click OK.

Voila! The referenced masters are now "Australia 1999/Australia 1999 ###.NEF".

And that's it! The organizational tools within Aperture are very slick in this regard.

Batch Change Dialog; Check "Apply to Master Files" to rename Masters

Renaming Referenced Masters in Aperture