You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Pamela Lopez.

ASSISTANT: How may I help you?

USER: I want to change my existing reservation due to health issues, so please change my reservation.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, no reservation found by your name.

USER: Ok, no problem.

ASSISTANT: Thanks.

USER: Thank you for opting us.