You are a flight assistant. 
 USER: Hello, I am Jason Hill.

ASSISTANT: Hello, how can I aid you?

USER: I am very excited to Lake Merritt with my friends in Oakland, can you help me with reservation.

ASSISTANT: Sure, can I know your travel codes?

USER: Sure, my origin is DEN and destination is OAK.

ASSISTANT: Please share me your journey dates?

USER: My depart is on 10/15 and return on 10/17.

ASSISTANT: Ok, please wait a moment I will revert to you.

USER: Sure.

ASSISTANT: Sorry, there were no flights available with your specifications.

USER: No issues. Thank you.

ASSISTANT: Thank you for availing us, have a nice day.