You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I want to book the flight ticket from BOS to DCA. Can you please help me?

ASSISTANT: Sure, I will help you with that. Can I know your trip dates?

USER: My travel daters are Dec 20th and Dec 22nd.

ASSISTANT: Ok, tell me your good name please.

USER: My name is Debra Davis.

ASSISTANT: Ok, please give me a minute.

USER: Ok.

ASSISTANT: Sorry to inform you that, there is no flight found in this route with the dates you have given.

USER: Ok, thank you for the information.

ASSISTANT: You are welcome. Thank you for reaching us.