You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you today?

USER: I am Kimberly Lewis.

ASSISTANT: Ok.

USER: I want to change my existing reservation, due to health issue. Can you help me out?

ASSISTANT: Sure, I am here to help you out. Your reservation is not recorded in the data base to proceed.

USER: Sure, take your time. Not an issue.

ASSISTANT: Thank you for opting us.

USER: Thank you for quick response.