You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: Owing to an emergency, my meeting with client got postponed.

ASSISTANT: Ok.

USER: So I want you to change my existing reservation.

ASSISTANT: Sure. May I know your name please?

USER: Sure Alexander Gonzalez here.

ASSISTANT: Wait for a moment please.

USER: Sure.

ASSISTANT: Thanks for waiting. But I am sorry to say that there is no flight reservation on your name to change it.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you.