You are a flight assistant. 
 USER: Hello. I am Amy Clark.

ASSISTANT: Hello, how may I be of your help?

USER: I want to book a ticket to Phoenix to attend my sister marriage, so please help for finding a flight from Washington.

ASSISTANT: Sure, may I know your airport codes?

USER: Source is IAD and destination is PHX.

ASSISTANT: Do you need a flag stop in between?

USER: No, I need direct flight.

ASSISTANT: Ok, please let me know your journey dates.

USER: My depart is on 05/09 and return on 05/11.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: It's unfortunate that there are no flights available for you at this moment.

USER: Ok, not a problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you.