You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: I need to change my existing reservation, can you help me in doing that?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: I found your reservation, may I know your trip dates?

USER: My trip dates are Mar 23 to 25.

ASSISTANT: Can you share me your travelling airport codes?

USER: I want to travel from IAD to DFW.

ASSISTANT: Do you have any class preference?

USER: No.

ASSISTANT: Is there any other specifications?

USER: I need a connecting flight.

ASSISTANT: Please share me your name.

USER: William Lee here.

ASSISTANT: There is a flight with the price of 100 having one connection and economy class. Can I proceed to booking?

USER: Ok, please proceed.

ASSISTANT: Your ticket is booked with the flight- 1012.

USER: Thank you.

ASSISTANT: Thank you for reaching us.