You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I want to change my existing reservation due to some issues, can you please help me with that?

ASSISTANT: Sure, can I know your name please?

USER: Sure, I am Michael Thompson.

ASSISTANT: We found reservation on your name, please help me with your journey dates?

USER: Sure, my journey dates are Sept 28 and Sept 30.

ASSISTANT: May I know your airport codes?

USER: I want to fly from DFW to IAD.

ASSISTANT: Do you have any connection limit?

USER: I need a flight with single connection.

ASSISTANT: Sorry, there are no flights found with your given details.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for opting us.