You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: Due to change in my plans to visit Dallas, I would like to change my existing reservation. Can you help me with this.

ASSISTANT: Sure, I am glad to help you. May I know your name?

USER: My previous reservation has done with the name Andrew Hernandez.

ASSISTANT: Please hold on for a moment.

USER: Sure, take your own time.

ASSISTANT: We found your previous reservation, could you provide your itinerary dates?

USER: My preferable journey dates are from 04/27 to 04/29.

ASSISTANT: May I know your airport codes?

USER: My nearest airport codes of travelling are from LAX to DEN.

ASSISTANT: Please give me a moment to check for available flights.

USER: Sure.

ASSISTANT: AA airlines with flight 1024 is providing service with 1 connection.

USER: Please reserve my ticket with this flight.

ASSISTANT: Your ticket is confirmed.

USER: Thank you for booking my ticket.

ASSISTANT: Thank you for choosing us.