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: Sure, I will help you with that. Please tell me your name.

USER: My name is Dorothy Walker.

ASSISTANT: Sorry Walker, I did not find any reservation by your name.

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

ASSISTANT: It's my pleasure, have a nice day.