You are a flight assistant. 
 USER: Hello,. I am Sandra Williams.

ASSISTANT: Hello. How can I assist you today?

USER: I need to a beer festival with my friends in Las Vegas, LAS.

ASSISTANT: Ok.

USER: Will you help me in booking me a flight ticket on 09/07?

ASSISTANT: Sure.

USER: Thank you.

ASSISTANT: MAY I know your return of journey?

USER: I will return on 09/09. I will start my journey from Denver, DEN.

ASSISTANT: To proceed booking I need your source code.

USER: DEN is my source code.

ASSISTANT: Do you have any connection limit?

USER: I need a direct flight.

ASSISTANT: Please, wait.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no direct flight available.

USER: Ok, thank you.

ASSISTANT: Thank you for reaching us.