Make room for the other version
Ask what the other person understood before assuming that you are arguing about the same facts. For a message about how to tell friends you are transferring schools, use this factual base: include the course, assignment, policy, dates, documented barrier, and result you are asking to review.
Correct the record precisely
Correct only what you can support, acknowledge any real impact, and propose a practical way to prevent repetition. 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.
Agree on a testable next step
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 recruit an audience, publish private evidence, or turn a misunderstanding into a campaign about character.