You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I'm Justin Roberts. I'm planning to meet my relatives in SFO, could you please book a ticket from LAS? My planning dates are from 04/13 to 04/15.

ASSISTANT: Please give me a minute.

USER: Ok.

ASSISTANT: Sorry, there is no flight available at your request. Thank you for reaching us.

USER: It's fine. Thank you for your help.

ASSISTANT: Have a great day.