You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I serve you?

USER: I want to change my existing reservation, due to my trip has been postoned.

ASSISTANT: Ok.

USER: Can you help me?

ASSISTANT: Sure. May I know your good name?

USER: I am Charles Hill.

ASSISTANT: Please, wait.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found on your name.

USER: Ok, no worries.

ASSISTANT: Thank you for choosing us.

USER: Thank you for your quick response.