You are a flight assistant. 
 USER: Hi, I am Mark Nelson.

ASSISTANT: Hello, how can I help you today?

USER: Please book me a direct flight from Boston to Oakland.

ASSISTANT: Sure, we are here to help you. Kindly mention your travel dates.

USER: Sure, my travelling dates are 01/17 and 01/19.

ASSISTANT: Could you please mention me your airport codes?

USER: Yes, my airport codes are MA-BOS and CA-OAK.

ASSISTANT: How much can you afford for this journey?

USER: I can pay up to 500.

ASSISTANT: Ok, please wait a moment.

USER: Ok.

ASSISTANT: Sorry to inform, no flights found with your requirement.

USER: That's ok. Thank you for the response.

ASSISTANT: Thanks for reaching us.