I get a telephone call from a client. They explain their problem, I tell them that I don't have a solution ready but I will look into it and get back to them. (don't call us, we'll call you)
I investigate and find my colleague is an expert in the matter. I talk to him, and he agrees to handle the problem. He asks me if I can send him an email, so he has an "official" demand and can answer properly.
Since I promised the client I'd answer, how should I act? If I don't notify the client that I transferred responsibility, and the client gets no answer, this'll reflect poorly on me. On top of that, I'd like the client to know my colleague will be handling his demand, so any new information or queries about progress should go to him.
Should I put the client in CC of the email I send my colleague? Will the colleague feel "forced"?