You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Stephen Rodriguez.

ASSISTANT: Stephen, how can I aid you today?

USER: I would like to change my existing reservation to Dallas, can you please help me with this?

ASSISTANT: Sure, I will help you. Please wait for a moment.

USER: Sure, take your own time.

ASSISTANT: I am sorry to inform you that there is no reservation found under your name in our website.

USER: Ok, not an issue. Thank you for providing information.

ASSISTANT: It's my pleasure.