You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

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

ASSISTANT: May I know your name please to check the reservation?

USER: Sure, my name is Michelle Johnson.

ASSISTANT: Michelle, there is no reservation found with your details.

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

ASSISTANT: Thank you for contacting us.