You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello there. Good Morning!!!.

USER: My friend has changed my plan to visit Dallas to Chicago, so could you please change my existing reservation?

ASSISTANT: How may I help you? sure. I can do that for you. just hold on for a moment. I am sorry but I din't find any reservation between these 2 places. May I assist you with anything else?

USER: My name is Gary Mitchell.

ASSISTANT: Can I know your name to  enter into our feedback generator. ? sure.

USER: Thank you for your help.

ASSISTANT: Thanks for your time.