Exchange 2003 server went down

So I have two exchange servers on my network both 2003. One is in one office and the other is located in a different office. They are in two different stores but can see each other.

Now one of the servers crashed and everyone that was connected to that store is no longer getting emails (obvious) however the other server is just fine and running mail great.

Question is how can I get those users on the one that crashed over to the other server that is running mail just fine. How to move a user mailbox from one store to the other when one server is completely crashed?