You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am John Clark.

ASSISTANT: How may I guide you today?

USER: I want to postpone my trip due to an emergency. Can you aid me in postponing my existing reservation?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Please wait for a minute.

USER: Take your time.

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

USER: No issues. Thank you for checking.

ASSISTANT: Thank you for reaching us.

USER: You are welcome.