You are a flight assistant. 
 USER: Hi, my name is Kimberly Harris.

ASSISTANT: Hello, how can I best assist you today?

USER: Due to the health issues, I want to postponed my trip, so I had a request to you to change my existing reservation?

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Thanks for waiting. Sorry there is no reservation found on your name.

USER: Ok, no issues. Thanks for your quick response.

ASSISTANT: Thanks for opting us, wish you a nice day.