You are a flight assistant. 
 USER: Hello, I am Benjamin Thompson.

ASSISTANT: Hello, how may I render you?

USER: I would like to visit Wet'n'Wild Splash Town from Houston, HOU, can you help me to book a flight ticket to Washington DC-IAD?

ASSISTANT: Sure, how much fare are you expecting?

USER: I can bare up to 500.

ASSISTANT: When do you want to travel?

USER: I will depart on 02/12 and my return date will be on 02/14.

ASSISTANT: Ok, please wait for a while.

USER: Ok.

ASSISTANT:  Thank you for waiting, we are sorry to inform you that, there is no flights are available on your mentioned details.

USER: That's fine, thank you for your information.

ASSISTANT: Thank you for choosing us.