You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Janet Garcia from Denver. I am planning to travel on these days that is 07/16 and 07/18. Can you find a flight ticket for me?

ASSISTANT: Yes, please provide me your airport codes.

USER: Ok, my airport codes DEN to IAD.

ASSISTANT: Garcia, there are no flights available.

USER: Ok, thank you for your information.

ASSISTANT: Thank you for reaching us.