You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: I am Mark Perez. Owing to an emergency, I want to change an existing reservation, could you help me in changing the reservation?

ASSISTANT: Sure, we are here to help you. Please wait a moment.

USER: Sure.

ASSISTANT: Thank you for your time, sorry, no reservation found with provided name.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for opting us.