You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I would like to change my reservation due to postpone of my engagement shopping. Please help me with it.

ASSISTANT: Sure, may I know your good name please?

USER: Sure, I am Karen Young.

ASSISTANT: Ok, please wait for a moment, I will check and get back to you.

USER: Ok.

ASSISTANT: Sorry, no reservation found with your name.

USER: It's Ok, thank you.

ASSISTANT: Thank you for opting us.