You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I am John Green, I want to change my existing reservation due to some health issues.

ASSISTANT: Ok. Please wait a minute.

USER: Sure.

ASSISTANT: Thank you for your presence. We found your reservation, please help me with your journey codes?

USER: Sure, my journey airport codes are DCA - ATL.

ASSISTANT: May I know your travel dates?

USER: My travelling dates are 07/14 to 07/16.

ASSISTANT: Do you need any other specifications?

USER: I want a direct flight.

ASSISTANT: Sorry, there is a connecting flight.

USER: Do not proceed. Thanks for your information.

ASSISTANT: Thank you for contacting with us.