We have a few custom fields setup for Building, Room # and Division. In the Building custom field I have it setup as a list (of buildings), but ran into trouble when I went to rename one of the buildings. I renamed the building and curious what it would do to all the past requests with that building and saw the building for those requests are now blank. It will let me make a new request with the new building but the old ones are all blank.
I have since changed it back to what it was and everything is back to normal.

What can I do?

I assumed that the building field was just a "pointer" that all the requests pointed to and by changing the building should update all the old requests to show the new building.