Recognize what makes this moment difficult
Acknowledge the event directly without turning it into a lesson, comparison, prediction, or silver lining. For a message about how to tell a professor you need to withdraw, use this factual base: include the course, assignment, policy, dates, documented barrier, and result you are asking to review.
Offer support that can be accepted
Offer one specific form of practical or emotional support and make clear that no immediate reply is needed. 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.
Follow their pace rather than yours
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. The recipient decides whether they want conversation, ordinary company, practical help, professional support, or quiet.