You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I render you?

USER: I am Charles Adams. I want to change my existing reservation, due to my health issue. Can you help me out?

ASSISTANT: Sure, I can help you with that. Let me check the status and revert you.

USER: Ok.

ASSISTANT: Thanks for waiting. It's unfortunate that there is no reservation found by your name.

USER: Not an issue. Thank you for your help.

ASSISTANT: Thank you for choosing us.