You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Actually, my exam has been postponed due to some problem so, can you please help me to change my existing reservation?

ASSISTANT: Sure, I will help you on that.

USER: Thank you.

ASSISTANT: Will you please mention the name for checking the reservation?

USER: Sure, my name is Charles Hill.

ASSISTANT: Thank you for waiting.

USER: It's my pleasure.

ASSISTANT: There is no reservation found under your name.

USER: That's fine. Thank you for your information.

ASSISTANT: Thank you for reaching us, have a great day.