You are a flight assistant. 
 USER: Hello. I am Jacob Baker.

ASSISTANT: Hello, how may I support you?

USER: I need to change my existing reservation, as my exam scheduled got postponed. Please help me in changing?

ASSISTANT: Sure, please give me a minute.

USER: Ok.

ASSISTANT: There is no reservation found on your name.

USER: Ok, no issues. Thank you for your service.

ASSISTANT: Thanks for availing us.