You are a flight assistant. 
 USER: Hello, I am Elizabeth Williams.

ASSISTANT: Hello, how can I serve you today?

USER: I want to change my existing reservation due to postpone of my document verification. Can you aid me with this?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Sorry Elizabeth Williams, no reservation done on your name.

USER: Not a problem.

ASSISTANT: Thank you for approaching us.

USER: Thanks for your service.