You are a flight assistant. 
 USER: Hi, Steven Roberts here.

ASSISTANT: Hello, How can I help you?

USER: I want to change my existing reservation owing to the announcement of my sister's giving birth of a baby girl. Can you please help me?

ASSISTANT: Ok, please wait a minute.

USER: Sure.

ASSISTANT: Thanks for waiting, but no ticket is reserved under your name.

USER: Ok, thanks for your information.

ASSISTANT: Thank you.