To add users to a thread, follow these steps:
1.Use an existing message for further thread in one of the following ways:
Select the message in the list with the left mouse button. Select the Menu Bar item >
Select the message in the list with the right mouse button. Run the context menu command .
2.In the message editing window that opens, add the necessary users in the fields To and Cc.
New recipients will be added to the discussion.