You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: My name is Justin Campbell. Can you please book me a plane ticket from LGA to SFO?

ASSISTANT: Please mention your trip dates.

USER: Sure, my trip dates are from 03/27 to 03/29.

ASSISTANT: Ok, please wait a minute.

USER: Ok.

ASSISTANT: There is no flight available.

USER: That's ok, thank you.

ASSISTANT: Most welcome.