You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I would like to travel from IAD to LAX as a business trip, can you do the reservation?

ASSISTANT: Can I know your travelling dates?

USER: My trip dates are 04/12 and 04/14.

ASSISTANT: Do you have any specification?

USER: I need only direct flight and departure time should be morning.

ASSISTANT: Can I know your name?

USER: Frank Hernandez here.

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

USER: No issue, thanks for the information.

ASSISTANT: Thank you.