You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How could I aid you today?

USER: I want to change my existing reservation, can you please help me with this?

ASSISTANT: Sure, may I know your name please?

USER: Thank you for accepting my request, I am Debra Smith.

ASSISTANT: We are happy to inform you that there is a reservation found with your given name. Can you please share me your airport codes?

USER: Sure, my airport codes are from EWR to CLT.

ASSISTANT: Kindly mention your travelling dates please?

USER: My trip dates are Jan 7 and Jan 9.

ASSISTANT: Let me know your requirements.

USER: I prefer a connecting flight in the business class which departs in the morning.

ASSISTANT: Sorry to inform you that there is no flight available with your matching information.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for availing us.