DS9 switched schools last September and it was challenging since he really doesn't like even minor change and that was a biggie. One thing that we did to get him to consider it was to sit with him and make a pros/cons list. For the cons we also brainstormed to see if there were things that we could do to minimize them. In the end we said that it was his choice but we strongly encouraged him to at least give it a try (school was such a HUGE disaster that staying wasn't really an option TBH). He finally agreed to try it but then 2 days in he declared that he wanted to go back to his old school. We knew that wasn't enough to make a decision so we then had to negotiate a length of time that was long enough for him to bother trying to make friends (he spent recess and lunch reading a book on the steps and didn't speak to anyone those days).
I don't know what we could have done to make it better but it was a rough 6 weeks for us. We even got to the point of meeting with the teacher because we wanted to get her observations before pulling him. After meeting with her it was obvious that it was actually a great fit and that we needed to stick it out. Then magically 2 days after the meeting that he didn't even know about he all of a sudden decided it was the best thing ever. It has been 7 months and he is a completely new kid and has convinced his sister to make the switch as well. Sorry that probably isn't much help but I figured I'd pass on our experience.
Good luck!
