You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: My vacation has been postponed.Can you please help me for cancelling the recent reservation?

ASSISTANT: May I know your preferable dates? Sure. Give me a minute?

USER: Ok. Can you please cancel the reservation based  on my name?

ASSISTANT: May I know your name please?

USER: Sure, my name is Gary Mitchell.

ASSISTANT: I am sorry to say that there is no reservation found.

USER: Ok, It's fine. Thank you for your information.

ASSISTANT: Thank you.