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

ASSISTANT: Hello, how can I assist you?

USER: I want to change my reservation as my plan to visit Denver to enjoy my holiday got postponed. Can you help me?

ASSISTANT: Sure, Please give me a minute.

USER: Ok.

ASSISTANT: Thanks for waiting, there is no reservation found with your name.

USER: It's Ok, thanks for your response.

ASSISTANT: Thank you.