You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Jacob Smith here.

ASSISTANT: How may I help you?

USER: I want to change my existing reservation due to postponed of my meeting dates. Can you help me in this?

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: Sorry, no reservation found by your name.

USER: Ok, no problem.

ASSISTANT: Thanks.

USER: Thank you for giving information.