จดหมายฉบับนี้เขียนเพื่อต่อรองราคาค่าอบรมสำหรับจำนวนคนที่มากขึ้นค่ะว่าสามารถลดราคาให้ได้ไหม  รบกวนช่วยตรวจจดหมายให้หน่อยได้ไหมคะว่าเขียนเป็นธรรมชาติและเหมาะสมหรือเปล่า ขอบคุณค่ะ  

Dear Mr. XXXXX

I apologize in the delay in replying. Thank you for your proposal. We sincerely appreciate the effort that you have put in submitting such a comprehensive proposal for our company.

My committee has looked into the quote and overall we were happy with it. At the same time we were going through an issue which had been outlined by our chairman.  In brief, the package cost you proposed was the one for 6-7 people per group, we are wondering if you can get us lower price for more people per group. Is it possible if you can reduce price for 10 people / 20 people / 30 people per group. If so, could you please give me the further detail?

I look forward to hearing from you at your convenience.

Yours Sincerely
XXXXXX