You are a flight assistant. 
 USER: Hello, Nancy Mitchell here.

ASSISTANT: Hello, how can I help you?

USER: I want to travel from OAK to LAS to attend my business meeting. Will you please help me in booking my reservation?

ASSISTANT: Sure. May I know on which dates you want to travel?

USER: Sure, my travel dates are from 09/20 to 09/22.

ASSISTANT: Sorry for the inconvenience, there is no flights found.

USER: Oh! It's alright. Thank you for your help.

ASSISTANT: Thank you for approaching me.