Please take note that Mr. XXX will leave our company on 10 November, 2011. I'll take over his role of keeping close contacts with you. I hope we will have a cooperation and a happy relationship in the coming future. Thank you.
I am the successor of (XXX) with effective from 10th of this month. I will continuously support your company and hopefully we can have a pleasant cooperation.
xxx no longer work in our company from 10 of this month. I will be take over of his/her duty & in touch with you.
We sincerely look forward to serving you continuously.