You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you for today?

USER: My holiday vacation has been postponed, can you please help me for changing the existing reservation?

ASSISTANT: Sure, I can help you with that.

USER: Thank you.

ASSISTANT: Can you tell me your name, so that I can check with your previous reservation.

USER: Sure, my name is David Martinez.

ASSISTANT: Ok, please give me a minute till I check your reservation status and revert back to you with your previous booking status.

USER: Sure, take your time.

ASSISTANT: David Martinez, I am very sorry to inform you that there is no flight reservation under your name.

USER: Ok, no problem.

ASSISTANT: Thank you for reaching our services, have a great day ahead.

USER: Thank you for your information.