Thank individual for his participation and suggest later participation. In every business communication course I teach, I remind the students to write clearly and simply. It has to be remembered a business letter requires a short space with a great deal said to convey the message. Get to the point, and stay with the point. In any business letter you have to worry about the tone or what sound is coming across to the reader.
Tone conveys the personality of the letter writer.
People like to read positive rather than negative thoughts. Now, let's write the letter we earlier planned. Look carefully at the format and the style of the communication. We welcomed your attendance and know you gained a great deal from the interaction with other faculty. At the moment, my commitments are reaching an impossible state with the faculty enrolled for credit.