You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I have planned a small hangout trip with my friends, but someone don't have manage his leaves, so we want to change our existing reservation. Can you help in that?

ASSISTANT: Good to hear that. Sure, I will help with the flight booking. Please hold on for a moment. I will check and get back to you.

USER: Sure.

ASSISTANT: May I have your name?

USER: I am Larry Collins.

ASSISTANT: Larry, thanks for your patience. But I am sorry to say that, there is no flight reservation on your name.

USER: Ok, no problem, thank you for your quick response in helping.

ASSISTANT: Thanks for reaching to us.