You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: As I am a scientist, I want to attend science festival with my students at Denver. Can you do the reservation?

ASSISTANT: Sure, please share me your travelling dates?

USER: Dates are 12/10 and 12/12.

ASSISTANT: Kindly mention me your airport codes?

USER: My airport codes are IAD-DEN.

ASSISTANT: Thanks for your details. Sorry there are no flights with your specifications.

USER: No problem, Thanks for the information.

ASSISTANT: Please provide me your name?

USER: Mary Williams here.

ASSISTANT: Thank you.