You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: Helen Evans here, can you help me to book a flight ticket from OAK to ORD?

ASSISTANT: Sure, please share your trip dates.

USER: Ok, please book for the dates Sept 12th and Sept 14th respectively.

ASSISTANT: Do you have any specifications?

USER: Ok, please book if the flight ticket price is 5000.

ASSISTANT: Sorry Helen Evans, no flight is available on your route.

USER: That is ok, thank you for assisting me.

ASSISTANT: Thank you for contacting us.