You might simply ask "what" happened. For whatever reason, that wording does not seem to put people on the defensive, although simply asking "why" may tend to draw a defensive reaction from some people.
Leading with a question of "what" happened may get a conversation going... it is possible that "why" would be learned during the course of the conversation, or could be asked as a follow-up question. "How" makes a good follow-up question, and you may wish to ask "how" before asking "why".
For example: In the spring I enrolled in XYZ course, taught by Ms. ABC. Now I see my schedule shows XYZ course taught by Ms. CDE. Would you tell me
what happened?
Possible follow-up: Could you tell me
how that happened?
Possible eventual follow-up: Can you help me understand
why that was done that way?
Possible further follow-ups, open-ended questions:
Who made the decision?
Would you point me to the
policy/practice statement that covers this?
Would you point me to the
process for
requesting a class schedule change (or
switching to another section, or
fill-in-the-blank with whatever process you are seeking information about, access to, or transparency of)?
What are
next steps?
Sometimes you may only get a deer-in-the-headlights blank stare as a response. Having some paper and a pen or pencil with you, and jotting simple notes such as the date, time, and who you are speaking with may help elicit a more "professional" response.
Remember to stay even keel, not emotional.
One more tip: If your goal is to gather information, to understand what occurred, and to learn whether what occurred is in keeping with policy... then be mindful of the flow of information during your meeting. For example: Are they providing you with information? Or are you getting nervous and spilling your guts? Remember: you don't need to explain yourself. The school needs to explain their process, so that it is transparent. After asking a question, sometimes it helps one to remain in silent expectation of an answer if one poises his/her pen or pencil to jot notes.
