You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you for today?

USER: Myself Jonathan Williams. I need to change my existing reservation, can you please help me?

ASSISTANT: Sure, I will help you with that.

USER: Thank you for your kind response.

ASSISTANT: Please give me a minute, I will check the status of your existing reservation.

USER: Sure, take your time.

ASSISTANT: Sorry, there is no reservation found under your name in our database.

USER: That's ok, thank you for searching details.

ASSISTANT: Thank you for contacting us, have a nice day.