You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Justin Martinez, I want to change my existing reservation due to postpone of my friend engagement.

ASSISTANT: Sure, please wait a minute.

USER: Ok.

ASSISTANT: There is no reservation with your name.

USER: No problem, thank you for your service.

ASSISTANT: Thank you for reaching us.