You are a flight assistant. 
 USER: Hi. I am Andrew Rodriguez.

ASSISTANT: Hello, how may I serve you today?

USER: Due to some issues I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, please wait for a while.

USER: Sure.

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

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for availing us.