You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you now?

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

ASSISTANT: Sure, I will help you with that. May I know your good name?

USER: Thank you. I am David Collins.

ASSISTANT: Please wait for while.

USER: Sure.

ASSISTANT: Thank you for waiting, I found a your reservation in our system data. May I know your airport codes?

USER: My airport codes are ORD and PHL.

ASSISTANT: Please mention your planned journey dates?

USER: My trip dates are Dec 16 to 18.

ASSISTANT: Please share your connection limit?

USER: No, thank you for asking.

ASSISTANT: Do you have any other requirement?

USER: No.

ASSISTANT: I found a connecting flight 1027 of airline Delta, fare is 100 and class is economy. Shall I proceed with booking?

USER: Ok, please proceed.

ASSISTANT: Your flight ticket has been booked.

USER: Thank you.

ASSISTANT: Thank you for reaching us.