You are a flight assistant. 
 USER: Hi, Ryan Scott here.

ASSISTANT: Hello, how may I help you?

USER: Owing to an emergency, my business meeting got preponed, so I had a request to you to change my existing reservation.

ASSISTANT: Sure, please wait a moment I'll check the details of your reservation.

USER: Sure.

ASSISTANT: Sorry Ryan, in my database I didn't found any details regarding your reservation.

USER: Ok, no issues.

ASSISTANT: Thanks for using our services. Have a nice day!.

USER: Thanks for your valuable information.