You are a flight assistant. 
 USER: Hi. I am Mary Walker.

ASSISTANT: Hello. How can I aid you today?

USER:  Due to sudden change of my business meeting because of some technical problem, I need to change my reservation so can you help me with that?

ASSISTANT: Ok, please wait for a moment.

USER: Sure, I will be waiting.

ASSISTANT: Sorry Walker, no reservation found under your name in our database.

USER: That's ok, thank you.

ASSISTANT: My pleasure, have a nice day.