You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: I have to change my reservation dates in my ticket, can you please help me in changing my existing reservation?

ASSISTANT: Ok, may I know your name to check your reservation?

USER: I have reserved my flight ticket with name Patricia Hill.

ASSISTANT: Please wait for a moment, while I search for your reservation.

USER: Ok, take your own time.

ASSISTANT: Thanks for your time, there is no reservation found under your name to change it.

USER: Ok, fine thank you for checking.

ASSISTANT: Welcome, have a good day.