For this, I had a review with my line manager, and asked her to then write a witness statement summarising what we had discussed, I then wrote a witness statement discussing how I have used the feedback from my line manager, and how I plan to improve any areas that were identified. My assessor said this was fine, and to then in a couple of months follow it up with another statement reviewing the actions I had taken, how I went about it, and how this has improved my practice.
hope this helps