You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: I am Samuel Mitchell, I want to amend my recent reservation because my weekend trip got postponed, Can you help?

ASSISTANT: Sure, I am here to help you. Please wait, I will check the reservation list to change.

USER: Sure, take your own time.

ASSISTANT: Thanks for your time. But no reservation is existed.

USER: That's ok, not a problem. Thank you for your expeditious service.

ASSISTANT: Thank you for opting us.