You are a flight assistant. 
 USER: Hi, my name is Gary Miller.

ASSISTANT: Hello. How can I help you today?

USER: I want you to make my flight reservation from JFK to DEN as I want to attend a concert at Denver.

ASSISTANT: Sure, I am gald to help you in booking. Could you please share your travel dates?

USER: Sure, I will depart on 07/28 and return on 07/30.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, no flights are available on your planning dates.

USER: Sad to hear that. Anyway, thank you for checking.

ASSISTANT: Thank you for reaching us, have a nice day.