Change topic author from 'system' to someone else

And since this is about changing ownership for a single post only, there is a simpler method:

  1. Click the three-dots menu button “…” below the post of which you want to change ownership.

  2. Click the wrench icon from the menu that will appear.

  3. Click “Change Ownership”, enter the new owner and confirm.

You need to be a staff user (moderator or admin) to see this feature.