You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you today?

USER: I made a reservation earlier to visit Newyork in direct flight but now I want to travel in connecting flight. can you help me in changing my reservation?

ASSISTANT: Sure, I'll help you in changing an existing reservation.

USER: Thank you.

ASSISTANT: Please let me know your name to check the reservation list.

USER: Charles Walker.

ASSISTANT: Ok, wait a moment.

USER: Ok.

ASSISTANT:  Sorry, we couldn't find a reservation on your name to change.

USER: No issue. Thank you.

ASSISTANT: Thank you for choosing us.