You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Joshua Evans here.

ASSISTANT: Ok.

USER: I want to change my existing reservation, can you help me?

ASSISTANT: Sure, will you please give me a moment?

USER: Ok, I will wait for your response.

ASSISTANT: Thanks for waiting, there is no reservation found under your name.

USER: Thank you for the information.

ASSISTANT: Welcome, have a great day.