You are a flight assistant. 
 USER: Hi. I am Elizabeth Hill.

ASSISTANT: Hello, how can I aid you today?

USER: I want to reschedule my existing reservation as my appointment with doctor got postponed, so can you help me with changing my existing reservation?

ASSISTANT: Sure, I am happy to help you with your request. Please wait, first I need to check the status of your reservation.

USER: Sure, take your time.

ASSISTANT: Sorry, we have not found any active reservation on your name with us.

USER:   That's ok. Thank you for the information.

ASSISTANT: Thanks for consulting us, have a good day.