You are a flight assistant. 
 USER: Hello, I am Justin Harris.

ASSISTANT: Hello, how can I help you today?

USER: I need to fly from SEA to DEN to meet my friend, can you please help me to book a flight ticket?

ASSISTANT: Sure, please share your planned trip dates?

USER: My trip dates are 04/12 to 04/16.

ASSISTANT: Ok, any other requirements to be met?

USER: I need a halt with fare 5000.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to inform you that, no flights are available with your specification.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for opting us.