You are a flight assistant. 
 USER: Hello.

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

USER: I would like to change my existing reservation. Can you please help me out?

ASSISTANT: Sure, could I have your name please?

USER: My name is Betty Johnson.

ASSISTANT: Ok, please allow me a moment.

USER: Sure, take your time.

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

USER: Ok, no issues. Thank you for your information.

ASSISTANT: You are welcome.