You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Jonathan Thomas here.

ASSISTANT: How can I aid you?

USER: I want to change my existing reservation, due to my grandfather health issue. Hoping that your me out.

ASSISTANT: Sure, give me a minute.

USER: Ok.

ASSISTANT: Thomas, I didn't find any reservation on you name.

USER: It's ok, thank you for checking.

ASSISTANT: You are welcome.