You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: Can you please help me to change my existing reservation?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: On whose name, the reservation has been made earlier?

USER: On my name, Nicholas Mitchell.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Thanks for your time, there is no seat reserved for you in any flight.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for opting us.