You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello,. How can I serve you?

USER: Can you help me in changing the existing reservation?

ASSISTANT: OK, please provide your name.

USER: I am Mark Jones.

ASSISTANT: OK, hold on I will check with the current status and revert you.

USER: OK.

ASSISTANT: Sorry, there is no reservation found with your name. Thank you, have a nice day.

USER: Thank you, for providing information.