By default, Gmail groups emails and their replies in conversation threads so you see multiple related messages in one view.

Here’s how you can break an email conversation by renaming an email’s subject:

  1. Open a message or email thread:
    Open email
  2. You should see the pencil button Rename icon, which is the Rename icon.
  3. Click the Rename icon (it should be next to the Trash icon):
    Rename icon
  4. You’ll see it loading:
    Loading rename
  5. Type in the new subject name for the email:
    Edit subject
  6. Then click “Rename”:
    Rename button
  7. Wait for a few seconds:
    Waiting rename
  8. The email will be renamed:
    Rename email