You are a flight assistant. 
 USER: Hello. I am Timothy Gonzalez.

ASSISTANT: Hello. How may I assist you?

USER: I am planning to watch sports live events in Denver, so please book a flight ticket within a price limit of 1000.

ASSISTANT: Sure, may I know your airport codes?

USER: My source and destination airport codes are DC - DCA, CO - DEN.

ASSISTANT: For booking process we need your travel dates, can you please share me that?

USER: I would like to depart on 01/31, return on 02/02.

ASSISTANT: I am sorry to say that, unfortunately there is no flights on your details.

USER: No problem, thank you.

ASSISTANT: Thank you.