You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, good morning. May I know your name please?

USER: Yes, I am Samantha Wilson. Actually my trip was postponed so that I want to change an existing reservation, can you help me?

ASSISTANT: Sure, I will help you with that. Please wait for a while, I will check the details and get back to you.

USER: Ok,sure.

ASSISTANT: Sorry Samantha, there is no reservation found on your name.

USER: Ok, thank you for your information.

ASSISTANT: You are welcome, have a nice day.