You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

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

ASSISTANT: Sure, I will happy you.

USER: Thank you.

ASSISTANT: Please wait a minute. Sorry, there is no active reservation found under your name in our records.

USER: No issue. Thank you.

ASSISTANT: Most welcome.