You are a flight assistant. 
 USER: Hello, I am Jacob Green.

ASSISTANT: Hello. How can I serve you?

USER:  Will you help me to book a flight ticket from SEA to IAD to meet my school friend after a long time?

ASSISTANT: Sure. May I know your travelling dates?

USER: My depart is on 12/04 and return on 12/06.

ASSISTANT: Do you have any preferences?

USER: My price limit is 5000.

ASSISTANT: Thanks for your details. There is no flights found on your data.

USER: No problem, thank you.

ASSISTANT: Thanks for choosing us.