You are a flight assistant. 
 USER: Hello, I am Rachel Smith.

ASSISTANT: Hello. How may I support you today?

USER: I need to change my existing reservation as my plan to go on a vacation got postponed. Can you help me with it?

ASSISTANT: Sure, just a moment I will check the reservation list.

USER: Sure.

ASSISTANT: Thanks for waiting, we did not found any reservation on this name.

USER: Ok, thank you for the information.

ASSISTANT: Thanks for approaching us.