You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, may I know your good name please?

USER: My name is Samuel Turner.

ASSISTANT: How can I assist you?

USER: I made a reservation earlier to meet my family doctor, due to unavailability of doctor on that days I want to change my reservation.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, we have no reservation found with your name to change.

USER: Ok, not a problem.

ASSISTANT: Thanks for choosing us.

USER: Thanks for the information.