You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I serve you?

USER: I am Katherine Harris, can you help me to change my reservation?

ASSISTANT: Sure. Please wait a while.

USER: Sure, take your time.

ASSISTANT:  Thank you for waiting, but I am sorry to say that, there is no active reservation found with your name in our database to change it.

USER: No issues, thank you for your information.

ASSISTANT: Thank you for choosing us.