You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you?

USER: Due to health issue, I want to change my reservation. Can you help me?

ASSISTANT: Sure, I am willing to help you for this. Could you share me your name?

USER: My name is Samantha Hernandez.

ASSISTANT: Please wait for a moment, let me check your reservation status.

USER: Ok.

ASSISTANT: Sorry to inform you, no reservation is found with your credentials.

USER: No issue, Thanks for the information.

ASSISTANT: You are most welcome.