You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: My self Melissa Carter. I need to book a ticket from DCA to PHX, can you help me in reserving a ticket?

ASSISTANT: Sure, may I know your travelling dates?

USER: My travelling dates are Sep 15 to Sep 17.

ASSISTANT: Do you have any requirements?

USER: I need one connection in my journey.

ASSISTANT: Sorry to say, no flight is available for you.

USER: Not a issue, thank you for your service.

ASSISTANT: Welcome.