You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I want to book a ticket can you help me?

ASSISTANT: Sure, please provide your name.

USER: My name is Patricia Rodriguez.

ASSISTANT: OK Patricia, please provide your travelling details.

USER: I want to book a ticket from NV - LAS to DC - DCA. My journey dates 03/11 & 03/13.

ASSISTANT: Please give me a moment.

USER: OK.

ASSISTANT: Thanks for waiting. Sorry to say that there is no flights found under your requirements.

USER: OK, thank you for checking.

ASSISTANT: Thanks for reaching us. Have a nice day.