You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am William Carter here.

ASSISTANT: How can I assist you?

USER: I want to visit Las Vegas, can you please help me to reserve my ticket from DCA to LAS?

ASSISTANT: Ok, when are you planning your journey?

USER: Sure, my preferable dates of journey is from 02/21 to 02/23.

ASSISTANT: Please give me a minute.

USER: Sure, take your time.

ASSISTANT: I found a flight in AA airlines with price 200. Shall I book the ticket for you?

USER: Ok, please proceed with this booking.

ASSISTANT: Your ticket is confirmed and the flight number is 1010.

USER: Thank you for your help in booking my ticket.

ASSISTANT: Thank you for contacting us.