Dear sir/madam:
[Organization] would very much like to have someone from your company speak at our conference on [topic].
As you may be aware，the mission of our association is to promote. Many of our members are interested in the achievements your company has made in.
Enclosed is our preliminary schedule for the conference which will be reviewed in weeks. Ill call you [date] to see who from your company would be willing to speak to us. I can assure you that well make everything convenient to the speaker.
Sincerely yours，
[name]