You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Richard Mitchell here, due to some personal work I want to change my recent reservation, can you help me to change this?

ASSISTANT: Ok, please wait a moment, let me check the status of your reservation.

USER: Sure.

ASSISTANT: There is no reservation found under your name to change it.

USER: It's ok, thank you.

ASSISTANT: Welcome.