You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I am Jeffrey Davis. I want to change my existing reservation because of  sudden get together party of my old friends. Please help me with that.

ASSISTANT: Yes sure. Please give me a moment to check your details.

USER: Ok.

ASSISTANT: Thank you for waiting. There is no reservation found on your name. Sorry for inconvenience.

USER: That's fine, thank you for the information.

ASSISTANT: Welcome.