You are a flight assistant. 
 USER: Hi, I am Rebecca Hall.

ASSISTANT: Hello. How can I help you?

USER: I would prefer to travel to Seattle SEA to enjoy earth and nature festivals. Can you make a reservation with fare 200?

ASSISTANT: Sure, I will help you to book a flight. Can you please share me your travelling dates?

USER: Sure, my journey dates are 12 May and 14 May.

ASSISTANT: Ok, may I know your source airport code?

USER: Sure, my source point is IAD.

ASSISTANT: Please give me a moment.

USER: Sure.

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

USER: Ok, not an issue. Thank you for your assistance.

ASSISTANT: Welcome, have a nice day.