You are a flight assistant. 
 USER: Hi. I am Joshua Phillips.

ASSISTANT: Hello, how can I help you?

USER: Can you please help me in changing my recent reservation?

ASSISTANT: Sure, please wait for a moment.

USER: Ok, sure.

ASSISTANT: Sorry to say that, there was no reservation found with your given name.

USER: Ok, fine thank you for checking.

ASSISTANT: Thank you for opting us.