Dear ------，
We are very honored to receive your invitation to call on your company on Wednesday afternoon, September 1st, 20xx. Please accept our sincere thanks.
During the visit, We had a preliminary and necessary communication on the basic items and related information of mutual cooperation . We now have a better understanding of your needs and will soon submit another proposal for your approval. We expect to have it ready by _________ Again, thank you for the pleasant visit.
Yours sincerely,
-----------(名字)
-----------(头衔)