You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I oblige you today?

USER: I am William Gonzalez. Owing to an emergency, I want to change an existing reservation. Could you please help me in changing the reservation?

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, no reservation found with your name to change.

USER: Not an issue. Thank you.

ASSISTANT: Thanks for availing us.