You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I best serve you today?

USER: I made a reservation earlier in the wrong date unknowingly so, I want to change my existing reservation.

ASSISTANT: Ok, may I know your name please?

USER: My name is Margaret Roberts.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

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

USER: Ok, no worries. Thank you for your kind service.

ASSISTANT: Thanks for opting us.