You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: Please help me in changing my recent reservation?

ASSISTANT: Can I know your name?

USER: Myself David Carter.

ASSISTANT: Reservation found. Can I know your airport codes?

USER: Ok. My  travelling codes are JFK to SFO.

ASSISTANT: Let me know your travelling dates.

USER: My travelling dates are Sept 02 and Sept 04.

ASSISTANT: Is there any connection limit?

USER: I prefer single connection flight.

ASSISTANT: Do you have any class preference?

USER: No.

ASSISTANT: Found ticket with United airlines for price 100 having flight number 1002. Shall I book a ticket?

USER: Please proceed with booking.

ASSISTANT: Ticket is booked.

USER: Thank you for your help.

ASSISTANT: Thank you.