You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I assist you?

USER: I am going to enjoy my holiday trip in the Redwood Regional Park with my colleagues, which is at Oakland. Can you help me in booking a flight ticket?

ASSISTANT: Sure, we are here to help you. When are you planning to travel?

USER: I want to travel on 08/27, and need to catch return flight on 08/29.

ASSISTANT: Please provide your airport codes.

USER: Source is from LAS. Destination is to OAK.

ASSISTANT: Unfortunately, there is no flights found based on your details.

USER: Ok, no issues. Thanks for the information.

ASSISTANT: May I know your name?

USER: I am Steven Walker.

ASSISTANT: Thanks for choosing us.

USER: Thank you.