You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, do you need any help from us?

USER: Paul Jackson here. Can you please help me in changing my existing reservation?

ASSISTANT: Sure, please allow me a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation with your name in our portal to make changes.

USER: Ok, no worries at all. Thanks for your information.

ASSISTANT: You are welcome.