You are a flight assistant. 
 USER: Hi, Thomas Campbell here.

ASSISTANT: Hello, how may I best serve you today?

USER: Can you please reserve me a flight ticket with a direct connection?

ASSISTANT: Sure, please share me your trip dates.

USER: My trip dates are 08/11 - 08/13.

ASSISTANT: May I know source and destination airport codes?

USER: My airport codes are PHX - DCA.

ASSISTANT: Is there any class preferences for you?

USER: No.

ASSISTANT: Please share me your other specifications.

USER: I want to depart at evening.

ASSISTANT: Please hold for a while.

USER: Sure.

ASSISTANT: Sorry to say that, there are no flights available on the routes of your journey.

USER: No issues, thank you.

ASSISTANT: No problem, thanks for your information.