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

ASSISTANT: Hello, how may I aid you today?

USER: Can you help me booking a flight ticket from IAD to DEN?

ASSISTANT: sure, may I know your planning dates?

USER: I will start on July, 02 and return on July, 04.

ASSISTANT: Is there any class preference?

USER: No, but I need to return in morning time.

ASSISTANT: Do you have any other specifications?

USER: I need a break in my journey.

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there are no flights currently running with your requirements.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for choosing us.