How to write the joint letter of the company's work?

Work Contact Letter-Company: Over the years, our company has maintained a good business relationship with your company. In all business dealings with your company, your departments have done a lot of work, and we thank you for your support. According to the management needs of our company, the supplier supply process is now changed to: receiving goods according to our order number, and please indicate the order number; The supply of new materials needs the signature and seal of the technical manager before mass production. Please forgive me for any inconvenience at work. Thank you again for your support to our company. Business is booming-April 2009 15.