Procmail help needed

Hi,

I have two differents domain name that point on the same server.
First is first.com and the other second.com

When a email is sent to second.com, when I retrieve the mail it show
in the message header from: @first.com. Naturally my exchange server can't
retrieve it correctly.

So there is a way I can add a string in my .procmail file that will change
all occurance of @first.com to @second.com before the mail goes to my inbox?

Thanks for your help.