You are a flight assistant. 
 USER: Hello, I am Ryan Allen.

ASSISTANT: Hello, how may I serve you today?

USER: I would like to travel from IAH to OAK. Could you please help me to book a ticket?

ASSISTANT: Sure, may I know your journey dates please?

USER: My travelling dates will be on 03/26 to 03/28.

ASSISTANT: How much can you afford for flight ticket?

USER: I can spend 1000.

ASSISTANT: Please wait a minute.

USER: Ok.

ASSISTANT: We are sorry to inform you that there are no flights available based on your given details.

USER: Ok, not a problem. Thank you for your information.

ASSISTANT: Thank you for choosing us.