You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I render you?

USER: Can you please help me to book a flight ticket from DCA to PHX?

ASSISTANT: Sure, please provide your itinerary dates.

USER: My travelling dates are May 22 to May 24.

ASSISTANT: Which class do you prefer?

USER: I prefer economy class.

ASSISTANT: May I know your name?

USER: Angela Davis.

ASSISTANT: Sorry Angela Davis, no flights are available on your route.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.