You are a flight assistant. 
 USER: HI.

ASSISTANT: Hello, how may I aid you?

USER: Owing an emergence, I want to change my existing reservation. Can you please help me with it?

ASSISTANT: Sure, please provide me your name.

USER: My name is Janet Williams.

ASSISTANT: Sorry, there is no reservation exist on your name.

USER: Ok, no issues. Thanks for the help.

ASSISTANT: Thank you for opting us.