You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you today?

USER: Katherine Evans here. I need to travel from SEA and IAD, can you please book flight ticket?

ASSISTANT: Sure, I am oblige to help you with that.

USER: My travelling dates are 12/08 and 12/10 and my budget is 500.

ASSISTANT: Ok, please wait a moment to check the flights availability within your requirements.

USER: Sure, take your time.

ASSISTANT: We regret to inform you that there are no flights moving to your region with your planned dates of travelling.

USER: That's not an issue, I will choose any other source to travel that place.

ASSISTANT: Thank you for reaching to our services, hope you have a great day.