You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I'm planning to visit my uncle's house at Washington, can you please find the tickets availability?

ASSISTANT: Yes, I will try for my best assistance. Can I know on which dates you will be travelling?

USER: I'm planning to travel on the dates of 12/26 to 12/28.

ASSISTANT: Ok, could you please share me your nearest airport codes?

USER: My origin airport code is SFO and destination airport code is DCA.

ASSISTANT: Hold on for a second, I will get back to you. Sorry to say that there are no flights found on your requested dates.

USER: Ok, not an issue. I'll find any alternate for this trip.

ASSISTANT: Can I know your name for documentation purpose?

USER: My name is Joshua Hall. Thank you for providing information.

ASSISTANT: Thank you for reaching us.

USER: Welcome.