Suggestion #22: Avoid surprises during less preferred activities or transitions.As I have said before, communicating with autistic children may be difficult. Even if they hear what you are saying, they may not understand. This is one of the reasons why setting up a schedule for them is so important, that way they will know what is happening, which lowers the amount of communication necessary. If they have a hard time transitioning from one class to another, and you (during their transition) change something on them with no warning before the transition starts, you could seriously throw them off. They may need all of their concentration to be on simply getting to the next class.
So please be certain to warn them if even the smallest thing might be different during this time. (Examples: we are not going to bring your back pack with us; a different TA is going to walk you to the class; we are not going to be having snack during this period, it will be in the next) No matter how small the change, they will have a hard time understanding why it has to change and they will need time to process and adjust to the fact that it has been changed. You would greatly increase the difficulty for them to process this information if they also have to transition at the same time.