How do I add new people to an existing Conversation?
You can add people to an existing thread in Conversations.
Open Compose Window
Click the Reply icon to open the Compose window.
Start to type a name in the the text field , or click the Address Book icon  to see a list of courses and groups.
Use Address Book
Click the Address Book icon  next to the To field. From the address book, locate the individual and select his or her name . Names are sorted by last name.
To navigate back to the course roster, use the arrow icon .
To exit the course roster menu, press Return (on a MAC keyboard) or Enter (on a PC keyboard).
Verify you added the correct person.
Note: You cannot change the course or the subject line.