You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello,. How can I provide assistance to you?

USER: Will you help me out in booking me a direct flight to attend an emergency surgery?

ASSISTANT: Sure, please provide your planned journey dates?

USER: Thank you. My trip starts on 12/26 I will attend surgery on 12/27 and I will arrival on 12/28.

ASSISTANT: How much you can afford for a flight ticket?

USER: 1000 is the budget.

ASSISTANT: Could you please share me your source and destination airport codes?

USER: Sure, I will board from IAD and return from OAK.

ASSISTANT: Please wait a moment, I will revert to you.

USER: Sure.

ASSISTANT: Thanks for waiting, there were no flights found with your given information.

USER: Ok, I will choose other airline. Thank you.

ASSISTANT: May I know your name please?

USER: I am William Gonzalez.

ASSISTANT: Thanks for choosing us.

USER: Thank you.