Changing Subject, forwarding to new address

Hi there...

I've spent the last couple hours sifting through the archives, trying
this and that to do the following (without avail, obviously!):

take incoming mail, change subject line to "XYZ" and forward the
message, with the new subject line, to XYZ(_at_)where(_dot_)iam(_dot_)com 
without losing
any information from the message sent.

Can someone please help me?  My head hurts...

Jill