You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello,. How can I oblige you today?

USER: Please change my existing reservation owing to an emergency.

ASSISTANT: Sure, we here to aid you. Let me know your name for checking the reservation.

USER: I am Michael Perez.

ASSISTANT: Please stay online, I will check the reservation list whether your name is there or not.

USER: Sure.

ASSISTANT: Thanks for your valuable time,  we did not find any reservation with your name Michael Perez in our database.

USER: Thank you.

ASSISTANT: Thank you for reaching us.