Gmail group messages and their replies by default in conversation threads so you see multiple related messages in one view.

Here is how you can break email conversations off renaming email subject:

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