You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

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

ASSISTANT: Sure, We are here to help you. Can I know your name?

USER: My name is Joshua Baker.

ASSISTANT: Please wait a while.

USER: Sure, take your time.

ASSISTANT: Thank you for waiting, but I am sorry to say that, there is no active reservation found with your name in our database to change it.

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

ASSISTANT: Thank you for reaching us.