Name the authority in your opening sentence
Say which agency issued the document, which tax period it concerns, and what part you need to understand. Keep the actual notice and a short list of available records beside you. If two authorities are involved, explain the connection without assuming their processes or required responses are identical.
Ask how the work would be organized
Use the telephone contact to discuss the tax-relief question, then clarify the proposed task, responsible person, fees, and method for sharing later correspondence. A document handoff needs a confirmed recipient and secure delivery process. Keep official response instructions separately visible during the conversation, and record any next task with its account, period, and owner instead of leaving those details to an assumption.