Rebuild the missing context
Assume the recipient will not remember every date, promise, or earlier conversation. For a message about how to apologize to a customer for a delayed order, use this factual base: confirm the order, charge, booking, or service problem and separate verified facts from what is still being checked.
Say what needs to happen next
State the decision, information, or practical action you need and include a real deadline only when one exists. Offer the available refund, replacement, correction, or escalation with dates and ownership. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Avoid making urgency into pressure
Do not use empathy as a substitute for a remedy or ask the customer to repeat information you already have. Move payment, privacy, accessibility, and product safety incidents into the documented specialist process immediately. Do not make the other person responsible for reducing the discomfort that prompted you to write.