You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I support you?

USER: I want to change my existing reservation under name Justin Mitchell.

ASSISTANT: Ok, please wait, let me check the status.

USER: Ok.

ASSISTANT: Thanks for your patience. There was no existing reservation found with your name.

USER: Not an issue. Thank you for quick response.

ASSISTANT: It's my pleasure to help you.