Change a Thread's Subject When the Topic Changes

Pivot the conversation without losing the thread

Woman using laptop at table
Tim Robberts / Getty Images

On mailing lists, message boards and in group emails, individual posts often spark lively discussions. As these discussions grow longer, the topic can change substantially. Usually, it has nothing to do anymore with the subject of the original message.

You can change the subject header line of a message thread when it becomes apparent that the topic of the discussion has pivoted.

Retaining the Original Subject

Depending on where you are, you probably can change the subject directly by typing a new one in the Subject line when you're writing your reply. But this may not be the best path to take. 

Rather than changing the subject, make it clear that you're continuing an old thread and not starting a new one by including the previous subject line with the new one.

If the original subject was "New cloud form discovered," and you want to change it to "The finest English umbrella," the complete new Subject line could be "The finest English umbrella (was: New cloud form discovered)." You can, and probably should shorten the original.

If you reply to a message with a (was:) block, remove it. It isn't needed any longer.

Caveats When Changing a Subject

  • Don't edit any of the earlier content or thread messages.
  • Don't remove the recipients of the earlier emails.
  • State why you are changing the subject to avoid confusion

Sometimes Starting Over Is a Better Choice

Changing the subject line to start a new conversation can lead to display problems for others and yourself. Email programs and services may lump together the wrong messages in threads.

To avoid this problem and the likelihood of being seen as "threadjacking," which occurs when someone takes over a thread or email discussion and intentionally posts on a subject unrelated to the original post, create a new message with a new topic instead of starting with a reply.