You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

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

ASSISTANT: Sure, may I know your name to check for the previous reservation?

USER: Sure, my name is Nicholas Martin.

ASSISTANT: Please allow me a moment to check for the previous reservation.

USER: Sure, take your time.

ASSISTANT: Nicholas, there is no reservation found under your name.

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

ASSISTANT: You are welcome. Thank you for contacting us, have a great day.