You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I want to travel from DFW to SFO, can you please help me to book the flight ticket?

ASSISTANT: Sure, can you please let me know your preferred journey dates?

USER: I want to depart on 09/19 and also book the return ticket on 09/21.

ASSISTANT: May I know your name?

USER: My name is Jennifer Green.

ASSISTANT: Sorry, there is no reservation found on your name. Sorry, no flight as per your details.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for choosing us, have a nice day.