Dear Mr. Ken,
With regards to your Annual Dinner, I won’t be able to attend after all because an urgent matter has cropped up and I have to go to England immediately to deal with it.
As for the speech you requested, I certainly would not be able to give any now. However, if you like, my partner, Mr. Peter can give one. He is highly experienced in this sort of thing and I am sure he can satisfy the audience. Give Peter a call on the matter. I am sure he will be happy to give the speech. Thank you.