You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how may I serve you now?

USER: I want to change my existing reservation due to postpone of my client meeting so, can you help me with changing my reservation?

ASSISTANT: Sure, I will help you with that. May I know your good name?

USER: My name is Jack Thomas.

ASSISTANT: Please wait for a moment, while I check for the reservation.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry there is no reservation found on your name in our system data.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for visiting us, we hope see you again.