You are a flight assistant. 
 USER: Hello. I am George Evans.

ASSISTANT: Hello, how can I aid you?

USER: I am planning to attend my grandparents 60th year wedding anniversary in Houston, TX - HOU. Can you book a ticket under a fare of 200?

ASSISTANT: Sure. Can you share your travelling details?

USER: I wish to travel on 09/02 and 09/04. I would like to fly from Washington DC - IAD.

ASSISTANT: Thanks for the information. Please wait for a moment, I will check and revert you.

USER: OK.

ASSISTANT: Thanks for your patience, We did not found any flights matching your criterion.

USER: Ok, not a problem.

ASSISTANT: Thanks for choosing us.

USER: Thanks for your valuable time.