You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you?

USER: My friend was hospitalised, so I couldn't make a journey right now. I need your help in changing the reservation.

ASSISTANT: I will surely help you.

USER: Thank you.

ASSISTANT: Can I have your name to check your previous reservation details?

USER: Previously, I have reserved my ticket with the name of Dennis Wilson.

ASSISTANT: Ok, let me check.

USER: Sure.

ASSISTANT: Sorry for the inconvenience, there is no active reservation found under your name in our database.

USER: It's ok, not an issue. Thank you for providing information.

ASSISTANT: You are welcome. Thank you for contacting us.