Have you ever sent an email to someone, we'll call that someone Dr. Bob Smartypants and then Dr. Bob Smartypants says "Oh, you need to talk to Dr. Charlie Smartypants" and then copies Dr. Charlie Smartypants on the reply, which includes both the text of the original email as well as all the attachments of the original email. But for whatever reason Dr. Charlie Smartypants does not engage in the "conversation". So then you have to choose to either send another email to Dr. Charlie Smartypants with basically exactly the same information that was on your original email to Dr. Bob Smartypants THAT HE HAS ALREADY SEEN BECAUSE HE WAS CCed ON THE REPLY EMAIL or wait a few days and see if he replies to the CCed email he received. And then if he doesn't respond it gets kind of awkward because there's this big "I know you have that email about that thing why are you not responding" elephant in the virtual room, but you have to do SOMETHING, right?
What are you supposed to do? Any etiquette experts out there?