Dear Mr. Henderson,
It was a genuine pleasure to receive your invitation to the upcoming linguistics conference you are hosting next month. Thank you very much for thinking of me; it is an honour to be included in such a prestigious event.
Regrettably, I will be unable to attend on this occasion. My firm has recently assigned me to an intensive project that requires my presence in Singapore during those exact dates. As this is a critical stage of the international rollout, my travel schedule is inflexible, making it impossible for me to join you in London.
Please accept my sincere apologies for missing what promises to be a fascinating seminar. I have followed your recent publications closely, and I was genuinely looking forward to hearing your insights firsthand.
I truly hope that you might consider inviting me to future sessions, as I would be delighted to participate in any upcoming events you organise once my current project concludes. I wish you the very best of luck with the hosting duties and hope the conference is a resounding success.
Best wishes,
Julian Thorne