You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may 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: Sure, we are here to help you. Can I know your name please?

USER: Thank you. My name is Eric Perez.

ASSISTANT: Sorry to inform you that there is no active reservation on your given name.

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

ASSISTANT: Thank you for contacting us.