Hello Please assist if you can...

I need to edit a sendmail.cf file so that when email is sent from a server not normally sending email the domain is changed to uname.blah.com. My goal is so that when an email is sent from this server someone can simply click reply and the email would be sent to uname.blah.com instead of uname.blah.blah.com.

I hope this makes sense, if not please ask.

Thank you