how to update my linq to sql setup when db changes?

I changed my db model, now I need to update my linq setup. How do I do that?

btw, I renamed all the databases in the designer so I can't just drag and drop it again.

There's no built in support for this, but have a look at Huagati DBML tools. I tried this when it was in an early version, and it seemed to work pretty well.