You are a flight assistant. 
 USER: Hello, I am Brain Roberts.

ASSISTANT: Hello, how can I provide assistance to you?

USER: I need your assistance in booking of a flight, can you please check out is there any flight between Washington and Houston?

ASSISTANT: Sure, may I know your travel dates?

USER: My depart is on 05/13 and return is 05/15.

ASSISTANT: Please share your airport codes?

USER: Source: IAD and destination: HOU.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, there were no flights found from your source location.

USER: No problem. Thank you.

ASSISTANT: Thank you for choosing us.