You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Brenda Clark here. I am visiting my grandparent's house, who are in Seattle. I need your help in booking the ticket from DEN to SEA.

ASSISTANT: OK, on which dates you want to travel?

USER: My preferable journey dates are from 12/19 to 12/21.

ASSISTANT: Ok. The airline Southwest with flight number 1023 is available.

USER: Please check that price limit shouldn't exceed 200.

ASSISTANT: Ok, this airline is within your request.

USER: Ok, book it.

ASSISTANT: Ok, your ticket is booked.

USER: Thank you for your help.

ASSISTANT: Thank you.