You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: Due to change in my plans to visit Dallas, I would like to change my existing reservation. Can you help me with this?

ASSISTANT: Sure, may I know your name please?

USER: My name is Debra Thompson.

ASSISTANT: Debra, can you please wait for a moment?

USER: Sure, I will wait for your response.

ASSISTANT: Sorry Debra, I have not found any reservation by your name in our website.

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

ASSISTANT: Thank you very much for choosing us.