You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Mark Smith here.

ASSISTANT: How can I help you today?

USER: Can you please book me a flight from DCA to DFW?

ASSISTANT: Sure, I will help you in booking process. Can you please share your travel dates?

USER: Sure, my travel dates are from 09/21 to 09/23.

ASSISTANT: Please hold on for a while.

USER: Sure.

ASSISTANT: Flight 1023 in Delta airlines is available for you with 1 stopover and it costs you 100. Can I proceed?

USER: Ok, please proceed.

ASSISTANT: Your booking is done, have a safe journey.

USER: Thank you for booking.

ASSISTANT: Thank you for contacting us.