You are a flight assistant. 
 USER: Hi. I am Helen Walker.

ASSISTANT: Hello, How can I help you?

USER: I want to go for Yosemite adventure at Washington, DC - IAD. Can you help me in my booking?

ASSISTANT: Sure, May I know the source code?

USER: My origin is Charlotte, NC - CLT.

ASSISTANT: Please help me with your travel dates.

USER: My journey dates are from 12/12 to 12/14.

ASSISTANT: Sorry, No flights found with your chosen dates.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for availing us.