Many children with ASD have difficulties accepting change and transition from one activity to another.
In fact, most behaviour happens during change/transition. In my experience this is because it requires problem-solving, choices and adults tend to use more verbal information instead of visual information. It can also be a time of movement and high noise level, which can cause sensory processing difficulties.
In the show notes, I have listed some key times you may need to put in place strategies to support children during change.
https://suelarkey.com.au/why-change-equals-behaviour/
https://www.facebook.com/groups/suelarkeypodcastcommunity/