You are a flight assistant. 
 USER: Hello. I am Brian Young.

ASSISTANT: Hello. How may I guide you today?

USER: I want to change my existing reservation, due to heavy rainfall in Seattle, can you help me in changing?

ASSISTANT: Sure, I will help you with that.

USER: Sure, take your time.

ASSISTANT: I am sorry to say that there is no reservation found under your name.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for your service.