You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I would like to change an existing reservation due to my health issues.

ASSISTANT: How may I help you at this moment? Sure, I am here to help you with that.

USER: Can you help me in changing an existing reservation?

ASSISTANT: Please provide me your name?

USER: I am Pamela Mitchell.

ASSISTANT: Ok, wait for a minute.

USER: Sure.

ASSISTANT: Sorry to say that, there is no reservation found on your name in our database.

USER: Ok, not an issue. Thank you or your information.

ASSISTANT: Thank you for consulting us.