Rebuild the missing context
Assume the recipient will not remember every date, promise, or earlier conversation. For a message about how to ask to reschedule a missed exam, use this factual base: include the course, assignment, policy, dates, documented barrier, and result you are asking to review.
Say what needs to happen next
State the decision, information, or practical action you need and include a real deadline only when one exists. Request the permitted remedy or meeting and be ready to complete the required work. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Avoid making urgency into pressure
Do not demand a grade, conceal misconduct, or ask another student to support an inaccurate story. Use safeguarding, disability, counseling, or emergency channels for bullying, abuse, health crises, or immediate risk. Do not make the other person responsible for reducing the discomfort that prompted you to write.