You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you at this moment?

USER: I am Thomas Lee. I would like to visit SFO to meet my sister, can you help me to book a flight ticket from IAH?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: My travelling dates are 23 and 25 of April.

ASSISTANT: Do you have any preferences?

USER: I am comfortable with any class.

ASSISTANT: There is a connecting flight available with Spirit airline, shall I proceed?

USER: Ok, proceed to booking.

ASSISTANT: Your booking is done with flight number 1005. Happy journey.

USER: Thanks for helping me.

ASSISTANT: You are welcome, have a nice day.