Determine Your Scope
The scope of an acknowledgement letter can be quite brief, a line or two, the objective of which is to notify the reader that a request has been satisfied. When a continuing dialogue is required, the scope may be broadened to include new information.
In the body of the sample acknowledgement letter the writer provides the name of her assistant, a second contact person with whom he can speak should she be unavailable to take his call. This establishes a line of communication that indicates her serious interest in exploring a further business relationship.