You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you at this moment?

USER: I want to change my existing reservation, due to my friend marriage was postpone. Can you help me with that?

ASSISTANT: Sure, I will aid you with that. May I know your name for further process?

USER: Timothy Wright here.

ASSISTANT: Ok, please hold on a moment.

USER: Sure.

ASSISTANT: There is no previous reservation available under your name.

USER: That's ok, no issues. Thank you.

ASSISTANT: Thank you for reaching us, have a nice day.