Hello.
user
Hello, how can I aid you?
assistant
I am David Miller. I planning to celebrate my daughter birthday at San Francisco, CA - SFO. Can you please help me with book a direct flight?
user
Sure, please can I have your planned dates?
assistant
I have planned my travelling dates are 04/20 to 04/22.
user
Please provide me your  origin.
assistant
My origin code is Washington DC - IAD.
user
Sorry, there are no flights with your requirement.
assistant
OK, not an issue. Thank you for the information.
user
Have a good day.
assistant