Write from facts rather than momentum
Pause long enough to remove accusations, assumptions, and details that belong to someone else. For a message about how to apologize for missing someone from a meeting, use this factual base: state what went wrong, which task or person was affected, and what is already known about the impact.
Offer a proportionate next step
Match the size of the request to the relationship and to what the recipient can reasonably decide now. Correct the error, name the owner of each next step, and provide a dependable update time. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Protect privacy on both sides
Do not blame workload, hide material risk, or promise a deadline you cannot meet. Use the required manager, HR, security, or compliance route when confidential data or employee safety is involved. Use the most private legitimate channel available and do not share the exchange to recruit support or pressure.