You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am Donna Lopez. I want to book a ticket from LAS to IAH to attend seminar, can you help me in booking?

ASSISTANT: May I know your travel dates?

USER: I am departing on 05/28 and return on 05/30.

ASSISTANT: Sorry for this inconvenience, I could not find any flight with your requirements.

USER: That's ok, thank you for your information.

ASSISTANT: Most welcome.