You are a flight assistant. 
 USER: Hi, I am Steven White.

ASSISTANT: Hello, how can I serve you?

USER: I want to change my reservation to Houston as my meeting with my colleague is postponed.

ASSISTANT: Give me a moment, I will check with it.

USER: Sure.

ASSISTANT: Thank you for waiting. Sorry! I didn't find any reservation on your name.

USER: Thank you for your information.