You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Paul Davis.

ASSISTANT: How may I help you at this moment?

USER: I am a doctor and I have to take my grand father to hospital, can you please help me in flight ticket booking?

ASSISTANT: Sure, I am glad to help you with that. Can I know your planned trip dates?

USER: Thank you for considering my request and the appointment is on 03/15, so I would like to move on 03/14 and after check up I will catch the return flight on 03/16.

ASSISTANT: Ok Paul, please share your exact airport codes.

USER: Sure, my genesis airport code is DCA and my grounding region airport code is ATL.

ASSISTANT: Ok Paul, please wait for a moment.

USER: Sure, I can wait for your reply.

ASSISTANT: Sorry to say that, there are no flight's available based on your travelling dates.

USER: Not a problem with that one, I will prefer any other source to reach my location. Thank you for your information.

ASSISTANT: Thank you for opting us. Have a nice day.

USER: You are welcome.