You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Paul Johnson here.

ASSISTANT: How may I assist you today?

USER: Can you change my flight ticket reservation? As I want to change my dates for my business meeting.

ASSISTANT: Sure, I am here to help you to change that reservation, please wait for a minute.

USER: Ok.

ASSISTANT: Sorry, I could not find any reservation with your name in our database.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thanks for choosing us, have a great day.