He/She (the teacher/誰々) changed the date of the teaching practice for me.
I have had the scheduled date of the teaching practice changed for me.
「特別に授業の日程を変えてもらいました」＝ He/She (the teacher/誰々) changed the date of the teaching practice for me. / I have had the scheduled date of the teaching practice changed for me.
誰に変えてもらったという情報によりますが、上記の文章は通じると思います。
ボキャブラリー
change ＝ 変える
date/scheduled date ＝ 日程
teaching practice ＝ 教育実習
have had changed ＝ 変えてもらった
イギリス 
