You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I provide assistance to you?

USER: As there is a sudden change in climate at my destination, I want to change my existing reservation. Can you help me with that?

ASSISTANT: Sure, I will kindly help you with changing a reservation. Please wait a minute, I will check your existing reservation and let you know.

USER: OK.

ASSISTANT: Thank you for waiting, there were no reservation matches with given name. Let me know your name?

USER: I am Timothy Anderson. Thanks for your service.

ASSISTANT: Thank you, have a nice day?