You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I have planned for the trip, but unfortunately postponed due to my health issue. So I need to change an existing reservation. Please help me with that.

ASSISTANT: Ok, may I know your good name please?

USER: Sure, my name is Kathleen Evans.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Its ok, thank you for searching.

ASSISTANT: Thank you for reaching us.