You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Catherine Edwards.

ASSISTANT: How may I assist you?

USER: I have planned to visit Dallas & Fort Worth on a business trip. Can you please help me to get a flight ticket?

ASSISTANT: Sure, may I know your travelling dates?

USER: My trip will be on dates of 05/24 and 05/26.

ASSISTANT: May I know your airport codes?

USER: My airports codes are DC-IAD and TX-DFW.

ASSISTANT: Sorry to say that there is no flight found.

USER: Oh!. No problem. Thank you for your help.

ASSISTANT: Thank you for contacting us.