You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. I hope you are good today, how can I help you?

USER: I am not feeling well, my doctor gave me an appointment for treatment at San Francisco hospital. Can you help me in booking a ticket?

ASSISTANT: Sure, I will help you. From which airport you are willing to travel?

USER: I am willing to travel from LAS.

ASSISTANT: What is your destination airport code?

USER: My destination airport code is SFO.

ASSISTANT: To know is there any flight available, please share your preferred travel dates.

USER: My travelling dates are 01/21 and 01/23.

ASSISTANT: Please wait a while, I will check and revert you.

USER: Sure, take your time.

ASSISTANT: Sorry to say, no service is provided by any airlines on your specified dates. May I know your name please?

USER: My name is Margaret King. Ok, no issue. Thank you for your information.

ASSISTANT: Thank you for opting us. Have a nice day.