On the nav bar, click the Activities menu, then select Discussions.
In the Discussions List page, click the topic name to view the discussion topic containing the thread you wish to copy.
Locate the thread you wish to copy, then from the thread’s context menu, click Copy Thread.
In the Copy pop-up window, select the Destination Forum and the Destination Topic from the respective drop-down menus.
Optional: Under Copy Options, select:
Delete original post after copy completes check box: Selecting this option will delete the original post from the current topic after the copy operation completes. The original post will still be visible in the current topic for users with the appropriate permissions.
Copy replies check box: Selecting this option will copy all replies to the post.