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

ASSISTANT: Hello, how can I serve you the best today?

USER: I want to surprise my sister by celebrating her birthday.So, can you book a flight ticket from Phoenix, PHX?

ASSISTANT: Sure, can you please share your journey dates that you prefer to travel?

USER: My preferable dates of journey is 06/25 to 06/27.

ASSISTANT: Please mention your destination airport code.

USER: Washington, IAD is my landing point.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: Thank you for waiting, we found a connecting flight in Southwest airline has fare 100. Shall I proceed?

USER: Yes, you can.

ASSISTANT: Your booking has been done.

USER: Thank you for your help.

ASSISTANT: Thank you for reaching us.