You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I am Rachel Campbell.

ASSISTANT: Ok.

USER: Please book me a ticket with the fare of 500 to meet my friends at Houston.

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: May I know on which dates you would like to travel?

USER: I want to travel on 08/31 and return on 09/02.

ASSISTANT: Let me know your airport codes that you wish to board and land?

USER: My airport codes are from OAK to IAH.

ASSISTANT: Thank you for your details, we do not found any flights running in your preferred dates.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us. Have a nice day.