You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation which is done recently due to some health issues, can you please help me in this?

ASSISTANT: Sure, may I know your name?

USER: Sure, my name is Nancy Brown.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: Sorry, there is no active reservation found with your name in our records.

USER: Ok, not an issue. Anyways, thank you for your service.

ASSISTANT: Most welcome.