You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: I am going to attend organic farming meeting at San Francisco. Can you please help me in reserving the ticket from LGA to SFO?

ASSISTANT: Sure, could you please share your departure and arrival day?

USER: I am planning my trip on Apr 21, and again I will return back on Apr 23.

ASSISTANT: Ok, could I have your name please?

USER: Myself Shirley Allen.

ASSISTANT: Ok, do you have any other requirement?

USER: I am flexible with direct flight.

ASSISTANT: Sorry, there is no flight on your requested travelling dates.

USER: Not a bi problem, anyhow thank you very much for your information.

ASSISTANT: You are welcome, have a great day.