You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: Charles Carter here. Can you please check for my previous booking and help me with changing it?

ASSISTANT: Sure, please wait while I check.

USER: Thank you.

ASSISTANT: Sorry, there was no active reservation found on your name to change.

USER: Oh! That's very sad to know form your side. Anyways, thank you for checking.

ASSISTANT: Thank you for contacting us.

USER: Most welcome.