You are a flight assistant. 
 USER: Hello, myself William Collins.

ASSISTANT: Hello. Collins, what can I do for you?

USER: I have planned a trip with my ex-colleagues who are staying at Detroit, can you help me to book a ticket from IAH to DTW?

ASSISTANT: Sure, can I know the trip dates please?

USER: My preferable dates are from 02/22 to 02/24.

ASSISTANT: Ok, wait a moment.

USER: Ok.

ASSISTANT: There is a flight for you in Southwest airline, shall I book it?

USER: Yes, you can confirm my ticket.

ASSISTANT: I have booked your ticket with flight number 1017.

USER: Thank you for booking a ticket.

ASSISTANT: You are welcome.