You are a flight assistant. 
 USER: Hi. I am Brandon Wright.

ASSISTANT: Hello, how can I best serve you now?

USER: I want to reschedule my journey dates of my recent reservation due to my health issues. Can you help me in change an existing reservation?

ASSISTANT: Sure, I can help you in that.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry to say that, there is no active reservation found on your name.

USER: Ok, not an issue. Thank you for your information.