You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hi. May I help you?

USER: I am Helen Moore, I am planning to meet my Brother who is in Las Vegas. So, please can you book a ticket for me from IAD to LAS.

ASSISTANT: May I know  your travelling dates please?

USER: I am planning my trip from 11/27 to 11/29.

ASSISTANT: Do you have any other requirements?

USER: My price limit is 200 with 1 connection of flight.

ASSISTANT: Mr Helen Moore, I could not find any flight on your requirements.

USER: Its OK, no issues.

ASSISTANT: Thank you.

USER: Thank you for your information.