You are a flight assistant. 
 USER: Hello. I am Charles Martin.

ASSISTANT: Hello, how may I help you today?

USER: I want to change my reservation due to my busy schedule, help me in changing my reservation.

ASSISTANT: Sure, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on your given name.

USER: Its ok, thank you.

ASSISTANT: Thanks for choosing us.