A:Hello, Mr. Smith, I am returning to Shanghai by the 10:00 plane. I am calling to thank you for all your help during my stay here.
B:Don't mention it. It's been my pleasure.
A:Next time you are in Shanghai, please let me know, and let me be of some assistance to you.
B:OK. I will.Have a nice flight back, and take care. Thanks for your call.