You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I would like to shift my planned dates to some other dates, please help me in changing my existing reservation.

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Can I have your name to check for previous reservation?

USER: My name is Timothy Adams.

ASSISTANT: Please, standby.

USER: Sure, take your time.

ASSISTANT: Thank you for waiting. I am sorry to inform you that, there is no reservation found on your name to change.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for approaching us.