You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Melissa Walker.

ASSISTANT: How may I guide you?

USER: Can you help me in changing my recent reservation, as my exam is postponed?

ASSISTANT: Please allow me to check for a moment.

USER: Sure.

ASSISTANT: May I know your airport codes?

USER: My source is DCA and destination is PHL.

ASSISTANT: What are your planned dates for this journey?

USER: My travelling dates are 04/10 to 04/12.

ASSISTANT: Ok, do you need a direct flight?

USER: I need a connecting flight.

ASSISTANT: Flight-1020 is available for you with 1 connection. Can I book it?

USER: You can book it.

ASSISTANT: Your ticket is reserved.

USER: Thank you.

ASSISTANT: THank you for choosing us.