You are a flight assistant. 
 USER: Hello, I am Sharon Anderson.

ASSISTANT: Hello, how may I oblige you today?

USER: Can you help me booking a flight ticket from OAK to DEN?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: When you are willing to travel?

USER: I will start on 10/21 and return on 10/23.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Thanks for waiting. Sorry, We could not provide you the flights at this moment, due to the run way problem at your destination airport.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.