You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am David Davis.

ASSISTANT: Davis, how can I help you?

USER: I am planning to have a round trip in Houston, can you please book me a ticket from IAH to HOU?

ASSISTANT: Sure, I will help you. Could you please let me know your travel dates?

USER: My preferable journey dates are from 02/19 to 02/21.

ASSISTANT: Ok, please wait for a while.

USER: Sure, take your own time.

ASSISTANT: There is a flight available with UA airlines and the ticket fare is 100 only. Is it ok for you?

USER: Please reserve my ticket with this flight.

ASSISTANT: Your ticket is confirmed successfully.

USER: Thank you for booking my ticket.

ASSISTANT: You are most welcome and thank you for choosing us.