You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: Due to bad weather conditions, my meeting got postponed. Can you help me to change my existing reservation?

ASSISTANT: Sure, I will help you.

USER: Good to hear that from you.

ASSISTANT: May I know on whose name did you reserved the ticket?

USER: Sure, I have reserved the ticket on the name of Brian Nelson.

ASSISTANT: Please wait a while, I will check and inform you.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry to say, there is no previous reservation on your name in our database.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for utilizing our service. Have a nice day.