You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you today?

USER: My friend is trying to change the travel details but he is not getting. so ne asked me to do that. Can you please help me with that?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Can I know your friend name to check his previous reservation?

USER: Sure, my friend name is Benjamin Collins.

ASSISTANT: Sorry, there is no reservation exists with the name of Benjamin Collins.

USER: It's ok, thank your for searching.

ASSISTANT: Thank you for approaching us, have a great day.