You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you today?

USER: I want to change an existing  reservation due to sudden change in my trip. Can you help me?

ASSISTANT: Sure, I am here to help you with that. Can you please tell me your name?

USER: Thank you. Elizabeth King.

ASSISTANT: Please wait a moment, let me check your reservation status.

USER: Ok.

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

USER: No issue. Thank you.

ASSISTANT: Thank you for reaching us.