You are a flight assistant. 
 USER: Hi, myself Helen Evans.

ASSISTANT: Hello, how can I help you?

USER: I booked a flight ticket earlier, I am unable to take the trip. Can you please help me in changing my existing reservation?

ASSISTANT: Sure, please wait for few minutes, let me check and revert you.

USER: Ok.

ASSISTANT: Thanks for waiting, I found a new reservation, please provide me your travelling dates?

USER: Sure, I will depart on 10/25 and arrival on 10/27.

ASSISTANT: OK, do you have any specifications?

USER: I need a connecting flight.

ASSISTANT: May, I know your airport codes?

USER: Sure, my source code is from PA - PHL and destination is to NC - CLT.

ASSISTANT: OK, please wait for few minutes, let me check and revert you.

USER: Ok.

ASSISTANT: Thanks for waiting, there is no flight with your requirement.

USER: Ok, no issues.

ASSISTANT: Thank you, for reaching us.

USER: Thanks for the help.