When a requester replies to an email how can they add additional email addresses?

When a requester replies to an email how can they add additional email addresses?

For example a requester creates and incident and the technician sends a reply. The requester then wants to reply but include another email address. There is no "To" field available or anyway for them to include another email address from what I can tell. Is this a possibility now by changing a setting and if so which setting?

Thanks,
Erick G.

                New to ADSelfService Plus?