You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Dennis Scott here, please help me in changing the my previous reservation.

ASSISTANT: Yes, just hold on for a moment.

USER: OK sure.

ASSISTANT: I'm sorry, there are no reservations found with your details.

USER: It's OK.

ASSISTANT: Thank you, have a great day.

USER: Thank you to take my query.