You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: I am Elizabeth Robinson. I want to change an existing reservation due to sudden change in my trip. Can you help me with this?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Thank you for waiting, we did not any reservation on your name to change it.

USER: No issue. Thank you .

ASSISTANT: Thank you for choosing us.