Get around 'process cannot access file, being used by another process' error?

Question

I'm trying to access a file that is being accessed by another process, and it's raising an IOException. This same process, spawns my process. Is there a way to get around this error?

This is a C# application.

Edit

On their side I don't know. On mine:

System.IO.StreamReader file = new System.IO.StreamReader("log.txt");