You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Ryan Lopez, want to go for Atlanta to exhibit all my painting in our university.

ASSISTANT: Sure, please share me your travelling dates?

USER: Please book a ticket on 12/26 and return ticket on 12/28.

ASSISTANT: May I know your airport codes?

USER: Sure. Airport codes are:Washington-IAD to Atlanta, ATL. I prefer to go with a connecting flight.

ASSISTANT: Sorry, there is no flight with your requirement.

USER: Ok, Thanks for the information.

ASSISTANT: Thank you for reaching us.