Tell clients about a price or terms change

I work in marketing at a construction firm. Help me tell clients about a change to our prices or terms.

Context: Material and labour costs move during a job, and what can be passed on depends on the contract or quote the client already accepted.

Before you start, ask me for anything missing from this list:
- What is changing, from when
- Who it applies to
- The reason
- Any notice period we must give

Then:
1. Say what is changing in the first two sentences.
2. Give the reason without apology or spin.
3. Say what stays the same and what the client can do.

Give me:
- The notice
- A short version for the website
- Likely questions with answers

Rules:
- Use only the facts I give you. Where something is missing, write [detail needed]. Never invent a number, a name, a quote or a source.
- Describe building work in general terms only. Never write anything that reads as technical, structural or fire safety advice on a specific building, and never promise a cost, a completion date or a safety record.
- Write in plain English, in our voice if I have given you a sample.
- Do not tell me what the rules or regulations say. If something may be restricted, flag it and I will check.

Finish with a list headed "Check before this goes out". Include these, plus anything else the director who approves marketing or our health, safety and quality lead should see:
- The price variation and notice wording in the contract or terms
- Which live projects and accepted quotes the change applies to
- Day rates and price guides on the website updated to match