You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am Helen Gonzalez, want to change my existing reservation. Please help me out with that.

ASSISTANT: Sure, give me a minute.

USER: Sure.

ASSISTANT: Sorry Helen, I could not find reservation on your name.

USER: It's ok, no issue. Anyway, thank you for your help.

ASSISTANT: You are welcome.