Dear Mr. Henderson,
Thank you very much for your kind offer to join the team at your new company. It was a pleasure meeting you last week, and I was quite impressed by your vision for the business and the innovative projects you have planned.
After giving the matter careful consideration, I have decided to remain in my current position. I have been with my present firm for five years, and I am currently leading a long-term project that is nearing completion. I feel a strong professional obligation to see this assignment through to the end, and I believe that leaving at this critical juncture would be unfair to my team and my employer.
However, I would like to recommend a former colleague, Sarah Jenkins, for the role. She is an exceptionally talented project coordinator who is currently seeking a new challenge. Given her extensive background in the industry, I am confident she would be a valuable asset to your organisation. I have taken the liberty of attaching her contact details to this email.
Thank you once again for your generous offer and for the time you spent speaking with me.
Yours sincerely,
James Sterling