You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you today?

USER: I am George Taylor.

ASSISTANT: Ok.

USER: I want to change my reservation due to postpone of my appointment with doctor at Philadelphia. Can you help me in my changing reservation?

ASSISTANT: Sure.

USER: Thank you.

ASSISTANT: Please wait for a while, I will let you know.

USER: Sure, I will wait for your response.

ASSISTANT: Thanks for your patience, but no reservation is found.

USER: That's ok, thank you so much for your service anyways.

ASSISTANT: Thank you.