How to modify a text inside of a bubble?

I'm trying to implement an edit functionality. so, if the user sends a message as
**Hey whats up?** and then sends second message as **John** . I want the text "John" to be added to the same bubble instead of creating a new one.

The entire text would be **Hey whats up? John** in the same bubble.

Can anyone help me with this?

The issue identifies chat bubbles and sent messages but no files, tests, or entry points. Start by tracing where successive messages are turned into bubbles and where their displayed text is stored. Done means a later message can be appended to the existing bubble as described, without creating a new bubble, with coverage for that behavior.

Written by the indexing model from the issue text.